Today is known as Blue Monday. It's supposedly the most depressing day of the year, calculated by arbitrary variables such as 'debt', 'motivation', 'weather' and 'need to take action'.

It's difficult to see how you would calculate such a formula, but they seemed appropriate values to raise as Nick Clegg stood to speak at Mansion House this morning.

The weather variable certainly indicated it was Blue Monday - just 1°c outside in the City.

The debt was there too. "Our economy is seriously out of whack," said Clegg. "Wages falling by 3% per year but executive wages have risen by 13%." He described this as "wholly unjustified".

The market of executive pay has become "closed and self-serving", he said. To remedy this, Clegg pointed to Liberal Democrat moves to create "a progressive income tax system" where "low earners keep more of what they earn".

In his most explicit statement on the subject yet, he said that someone who sits on one remuneration committee shouldn't sit on any others, confirming that Vince Cable will be publishing the details of reforms in this area in the next few weeks.

He also indicated that he wanted to "alter boardroom behaviour". He said shareholders will only need to look at one number to understand what executives are paid and that the way money is spent needs to be "crystal clear".

So what about the ingredient of 'motivation' attributed to Blue Monday? The DPM seemed well aware that he is not the frontrunner on the subject of 'good capitalism'. "Another week and another speech about responsible capitalism," he joked.

But "Lib Dems have been arguing for a balanced capitalism for many years... New political vogue but not new for us." Party funding, too, a long time hobby-horse for his party, got a look in as Clegg chipped away again on that issue.

He also wanted to be clear that the Lib Dems have a stronger motivation than other parties. "I welcome a lot of what Ed Miliband said [last Tuesday]," Clegg stated, but he criticised Labour for being "in hock to trade unions".

In fact, he said the failures can be attributed to "a political failure, a regulatory failure and a market failure".

"Politicians in the pockets of vested interests," he said, using the example of Labour and the trade unions. and "regulators asleep at the wheel".

Finally, Clegg took on the final variable to classify a Blue Monday, 'need to take action'.

The deputy prime minister said: "We don't believe our problem is too much capitalism - we think it's that too few people have capital... we need more individuals to have a real share in their firms, more of a John Lewis economy."

So Clegg had all the ingredients for a depressing Blue Monday speech, and yet he was pretty upbeat about the future of capitalism. It may be "today's political punchbag" (the Liberal Democrats know what that feels like), but he was pretty optimistic about introducing change.

There's a comparison to his party's electoral fortunes in there somewhere.

Expect more market reforms along Liberal lines from Vince Cable in the coming weeks.

Tags: Capitalism, City, Liberal Democrats, Mansion House, Nick Clegg, Vince Cable