Political dining can be a jolly, anecdote-laden affair. But, Sarah MacKinlay and Ben Duckworth reveal, it can also be a setting in which plots are hatched, coups planned, and careers destroyed.

The boozy lunch is an integral part of many industries, but to journalists and politicians it is in the blood. The exchange of information, the stories, revelations, gossip and plotting that emerges from them is legendary. And such lunches are responsible for shaping much of our modern history.

Nothing could be considered more legendary than the spot on a busy street in Islington, north London where the Mexican restaurant Desperados sits. Until 2004, it was the site of Granita - scene of one of the most infamous political deals in recent history. In May 1994, the then shadow home secretary, Tony Blair, sat down with his friend and increasing rival Gordon Brown to thrash out the details of how Brown would stand aside to allow Blair to run for leadership of the Labour Party. Legend has it that Brown ate nothing, while Blair chose rabbit. The ramifications of the meal were huge and defined the Labour government from 1997-2007: Brown stewed in No 11, wondering when his allegedly promised chance to be Prime Minister would come, while Blair became increasingly exasperated with his hugely powerful chancellor. As an example of how meals make political history, Granita is unsurpassed. While the old restaurant has changed, it is still possible to sit at the same table 13 in the current establishment and imagine the scene over a taco and margarita.

But the Gay Hussar on Greek Street, Soho, is a far more enduring institution than Granita. Established by a northerner, Victor Sassie, in 1953, and inspired by the pre-war Budapest restaurants in his youth, it continues to thrive. Endless stories have emerged from its closely packed interior due to its long association with Labour and its affiliates.

First patronised in the late 1950s by Bevanites (although oddly not Bevan himself), its regulars included Barbara Castle and Michael Foot. Fleet Street followed in the 1960s as the restaurant gained an unparalleled reputation as a centre of gossip and intrigue.

Stories include George Brown, Harold Wilson's Foreign Secretary being ejected by Sassie for groping a female customer. Later, Mick Jagger was invited to enter politics in the private dining room on the second floor by Tom Driberg, the notoriously promiscuous Labour MP. Sadly, the Rolling Stones frontman declined.

While the folklore helped the Hussar become widely popular, it came at a price. The restaurant suffered a huge decline in political clientele after the Daily Mail published on its front page the enormous bill from a function hosted by the Shop Workers' Union for a Soviet delegation. However, the Gay Hussar won them back and it was the place where, in 1982, Tony Blair met Lord Pendry and first considered standing as an MP.

The owner became legendary in his own right and was happy to discuss his belief that the decline of the Labour Party in the 1980s was due to the extremism of politicians who didn't dine at his restaurant. Victor Sassie died in 1999 but the Gay Hussar continues to attract politicians. In 2003, Michael Foot celebrated his 90th birthday there and even Henry Kissinger has enjoyed the Hungarian cuisine. There are now 60 caricatures of politicians lining the walls, drawn by cartoonist Martin Rowson.

A little further on from the Gay Hussar on the corner of Greek Street lies the wild, but tired Coach and Horses. The bar is a favourite with media luvvies who enjoy its ‘old school' vibe. It was also a favourite of the journalist Jeffrey Bernard. Indeed, the interior of the pub was recreated on stage for the acclaimed play covering Bernard's life, Jeffrey Bernard is Unwell. The artist Francis Bacon also spent time there, as did the columnist Graham Mason, whose Telegraph obituary revealed: "Graham Mason, the journalist who has died aged 59, was in the 1980s the drunkest man in the Coach and Horses, the pub in Soho where, in the half century after the Second World War, a tragicomedy was played out nightly by its regulars."

Upstairs, the worn carpets, creaking floorboards and rickety tables remain, as do the photographs of past times - Images of Bernard and happy days. This is also the venue of the infamous Private Eye lunches, which are always filled with gossip and intrigue. One journalist told us that he witnessed an MP get so drunk that, when they both attended the same event later that evening, he couldn't even put his bow tie on.

The Guardian sketch writer Simon Hoggart is no stranger to the political lunch and has many stories to rattle off. One of his memorable experiences was a lunch with Enoch Powell and a small group of junior lobby journalists. The meal took place at Locketts, the restaurant in Marsham St which became Green's and is now Shepherd's, and is usually full of pinstripe-suited lobbyists buying roast beef and claret for Tory MPs.

Enoch began by ordering tripe. "We shall be talking it, so I may as well be eating it too," he told the assembled group with a certain grim satisfaction.

Hoggart explains what happened next: "We were in the mid-1970s and Harold Wilson was Prime Minister, just. Ted Heath had been expected to win the 1974 ‘who governs Britain?' election, but Wilson scraped back in, almost certainly with a little help from Enoch, who had left the Tories and encouraged people to vote Labour because they had promised a referendum on Europe.

"We asked what he thought about the government, and he replied that he felt about them much as one might about one's own children: ‘you might not agree with them, you might not even like them very much, but you cannot escape the fact that if it were not for you, they would not be there.'"

By the end of the lunch Hoggart had been nominated to see Enoch out of the restaurant. As they moved towards the cloakroom, Powell commented: "I am very glad you are accompanying me. You have saved me from what might have been a most embarrassing incident."

Hoggart was aghast: "I remembered to my horror that the cloakroom attendant was a young black woman. Was Enoch preparing to tell her to go home? Was he afraid that she might launch a tirade against him?

"‘You see,' he continued, ‘I must give the young lady a tip, and I have no change with me at all. Now if you have 50p'."

Another embarrassing episode ensued at the same restaurant, while lunching with John Gummer. He was Environment Secretary, and had arrived swathed in a magnificent suit of gorgeous fabric and flattering cut. He wore a similarly expensive shirt and a splendid yellow silk tie. Gummer told Hoggart that he had an important meeting with Brazilian environment ministers at 2.30, so just had time for a coffee.

They brought a large cappuccino. Gummer was making a point with particular vehemence, and brought his hand crashing down onto the saucer.

Hoggart says: "The monsoon of coffee, a sort of reverse Niagara, went all over his suit and shirt. The tie looked especially fetching because it caught most of the grated chocolate. Waiters rushed up with damp cloths. I sat making sympathetic noises while all the time feeling that wondrous sense of relief that it was not, in any way, my fault."

The Cinnamon Club is another fine venue nestled deep in the heart of Westminster, and is a favourite haunt for many journalists. Its popularity is probably in part due to its discreet dining area. Indeed, the club's entrance is so subtle you'd be forgiven for walking straight past it. Set just behind the opulent grounds of Westminster Abbey among clerical outfitters, The Cinnamon Club sits on the site of the old Westminster Library which opened in 1893. It was converted into the Cinnamon Club in 2001 by it ambitious founder Iqbal Wahhab. Guests include Prime Minister Gordon Brown, Jack Straw, Charles Clarke, Ed Miliband, Ken Clarke, Alan Duncan, David Cameron, Cherie Blair, Lord Puttnam; celebrities including Jude Law, Reese Witherspoon, Goldie Hawn; and cricketers such as Nasser Hussain and Sachin Tendulkar.

Aside from being a restaurateur, Wahhab dabbles in politics too. He chairs the Department of Work and Pensions' ethnic minority advisory group and sits on the ministerial ethnic minority employment task force. He sits on the boards of the London Development Agency business leaders advisory group, as well as two Business in the Community organisations - Mosaic and Race For Opportunity.

The club's head chef, Vivek Singh, used to run the kitchens at the Rajvials in Jaipur, where he was charged with treating guests to meals fit for a Maharajah. It would appear that he has brought these sentiments with him.

Slightly further afield in north east London, in a quiet spot in Bloomsbury, lies the North Sea Fish Restaurant - an unofficial trade union diner because of its close proximity to the offices of major unions including Unison, the NUT and the RMT. It was a favourite hang-out of Arthur Scargill, who would hold secret meetings with trade unionists and strategise about how they would deploy flying pickets. It was said to have been bugged by MI5, who never refuted the claim, but it is unlikely the police would have learned of the plans otherwise.

Mary Maguire, head of press and broadcasting at Unison, is one of the restaurant's most loyal customers of almost 30 years. "The North Sea was, and still is, the place we go to plot our strategies - we usually sit at the back upstairs so that we are not overheard," she says.

Recalling the time she was about to enter a particularly diffi cult industrial dispute, she tells how she sauntered over to the North Sea with her press team to plot a strategy over lunch. "We needed to keep public support and sympathy and make sure that the dispute was settled quickly.

"The North Sea used oblong squares of sturdy white paper, with wavy edges, as place mats. They were perfect for writing on. We came up with a good plan and, feeling pleased with ourselves, ordered a bottle of wine to round off the meal. Imagine my horror to discover that our carefully constructed strategy had been cleared away with the plates. I had to fi sh the place mats (literally) out of the bin. Apart from being a bit crumpled, and with the odd stain of tartar sauce, they were still fi t for purpose." The deal thankfully worked out well and she was successful in securing a deal for thousands of low-paid public-sector workers.

Political dining isn't exclusive to Westminster or London. Tongues were set wagging in September 2006 when two Brownite Labour MPs met in the Bilash Bangladeshirestaurant in Wolverhampton to discuss an attempt to force Tony Blair out of office.

The Bilash is not your average curry house. It has won countless awards and boasts several West Midland MP regulars. Tom Watson and Sion Simon enjoyed a biryani before deciding on their course of action. The fruit of their labour was a letter, later signed by 15 MPs and leaked the next day, calling for Tony Blair's resignation. Almost all the signatories have served in government under Gordon Brown, including Chris Bryant, now at the Foreign Office.

The most senior of the plotters, Watson, then a defence minister, was called "disloyal, discourteous and wrong" by Blair. He was discovered to have visited Gordon Brown's Scottish residence in North Queensferry the day before the letter was sent, but claimed to have simply been dropping off a present.

The curry house coup showed that, while political dining can be a jolly, anecdoteladen affair, it can also prove highly dangerous. Indeed, lunch can be deadly!