"Gordon Brown lost Labour the election." This is a phrase you may have heard in the immediate aftermath of those five days in May. But, my gosh, did Nick Robinson hammer this home in last night's Five Days that Changed Britain on BBC2.

Lord Mandelson shared the sentiments of woe. He told Robinson that, in a Saturday night phone call, Clegg may have found the PM "a bit Gordon-ish". Personality really was as important as policy, according to Robinson. Clegg recalled bruising the PM’s "pride" in telling him a Lab-Lib coalition with Brown as premier would be untenable. Brown appeared to be the man most at fault in the programme, perhaps a cruel by-product of not being interviewed.

But even as the bullish PM offered to step aside on the Monday, Robinson asserts that the Labour negotiating team just gave up. A key player in this loss was Ed Balls who even in his retelling of the frosty, unorganised talks with David Laws and co, seemed arrogant and bullish.

The programme sheds light on the future role of Vince Cable. His discomfort with the coalition was plain to see, having secret phone calls with Brown. Ming Campbell even claimed that the Liberal Democrats should avoid looking like a Tory "pet".

William Hague could deny it all he liked, but the Conservatives obviously had a coalition back-up plan — putting an 11-point policy paper on the negotiating table for the Lib Dems. This slick attack broke any chance of a Lab-Lib deal. The programme failed to convey exactly how fooled the media was into believing a Clegg-Brown deal was possible on Monday night. Instead, Robinson blamed the "rolling scrum" of the press, the heat and the changing markets on why negotiations appeared so confused.

Nick Robinson seemed to class every moment of those five days as a turning point. Certainly the fragile economic situation explains the surprise switch in Liberal Democrat negotiations on the Monday (when they sprang immediate spending cuts on Labour). But it also shows us a party not led by the Conservatives’ budget plans, but forcing through spending cuts in the fabric of coalition policy. The key factor of the decision seemed not to be in speeches or events, but in the personalities of Ashdown, Laws, Balls, Brown and, above all, the amazingly natural partnership between Clegg and Cameron.

"Five days that changed Britain" is available on BBC iPlayer now.