Bernard Donoughue: After the handshakes, reality looms for these unlikely political partners

I confess that I did not expect a formal coalition since I was assured that the Conservatives could not offer electoral reform to the Liberal Democrats and that Nick Clegg could not do a deal without it. In the event, David Cameron pushed his party into unexpected generosity in this area and Clegg took the bait with relish.

However, once the pleasure and relief of getting a government into place is over, Messrs Cameron and Clegg may find that the day to day business of running a coalition is not as easy as yesterday's initial handshakes on the steps of Number 10 suggest.

Of course, the basic fact is that no living politician in the UK has experience of coalition government (though our friends in Ireland and on the Continent do). We have not experienced it since the wartime government of Winston Churchill and war is not a relevant precedent to what faces us today.

The nearest precedent is the Wilson-Callaghan governments of 1974-9, which I served in Number 10. That was not a coalition time. We occasionally had a small majority, were often a minority, but usually managed to cobble together support for major legislation. For short periods, we had pacts with the Liberals in 1977-8 and with the Ulster Unionists in 1978-9. Although different from coalition, those experiences suggest a number of lessons from what might be termed "non-majority party government".

The first is that personalities matter. The then Liberal leader David Steel got on well with Labour PM Jim Callaghan, both straight men concerned with the national interest. I sense that David Cameron and Nick Clegg, of similar age, class and school backgrounds, will also sit easily together. (Clegg has always struck me as close to the Tories by background and instinct).

More difficult for them, and especially for Clegg, will be to carry their parties in coalition when the going gets tough. Steel could do that because the then Liberals were similar to Labour, being mainly a party of the democratic Left. Today's Liberal Democrats are a mixed bag. The main test will come when Cameron is pushing unpopular policies and the Lib Dem MPs find their constituency support ebbing away towards a possibly refurbished Labour Party which is now left alone occupying the radical opposition ground. When the going gets tough, many grassroots Lib Dems may go.

The most frequent difficulties in running the coalition may come on daily matters of routine functions and protocol. Who takes precedence in the Commons when David Cameron is away? Who represents the Government abroad and on ceremonial occasions.?

There will be much jockeying for position. Will Cameron consult Clegg – or even seek his agreement – over reshuffles and ministerial appointments at all levels, including those that solely involve Tories? How about big public appointments when both parties seek the spoils? Commissioners to Brussels will excite Lib Dem interest.

By-elections will be very difficult. Will the Lib Dems opt out of

contests against the Tories which they might have won? Their grass

roots activists might grumble and wither.

The referendum on electoral reform, at the heart of the coalition agreement, will present a mighty challenge – even about its wording.

We had a referendum on staying in Europe in 1976. Harold Wilson had to allow Cabinet colleagues to campaign for or against, which might provide a precedent. But in 1976, all main party leaders agreed on a yes vote. On electoral reform, the Tory and Lib Dem colleagues will be campaigning against one another, as will their parties in the constituencies. This is not likely to create harmony. It will prove fractious and could be fatal. An early test will be the conduct of the Thirsk and Malton election later this month, delayed because of the unexpected death of the Ukip candidate.

This coalition could succeed. If it successfully resolves our economic problems, that could provide considerable political cement, but the political cement of facing the Nazi threat under the great leadership of Winston Churchill was impressively more adhesive from 1940-45.

The problems facing this experiment should not be underestimated. The politicians conducting it have no experience of working together in government. Once the first excitement of a new government passes, we will become more aware of the fissiparous pressures at work.

This especially applies to the Lib Dems, where the intoxification of office has understandably been only too apparent, especially with their leader (and Mr Clegg should know from history that the post of Deputy Prime Minister is usually meaningless and impotent unless combined with a major department).

By the end of this year, the pain and blood of the public expenditure cuts and tax rises will be apparent throughout the land. The Lib Dems will feel the blame for that. Their backbench MPs and activists who don't have the consolations of office and who face hostility in the constituencies will feel the stress.

Those among them who don't like the Tories anyway may find it difficult to defend what is essentially a Tory government. Labour, as the sole opposition party, may come to be relieved that it did not participate in a coalition.

It is not necessary to be pessimistic. From the national interest, it is good that a government with a majority has been formed. If it

resolves our economic problems, the next election could give its gratitude and blessing to Mr Cameron. And if he also manages to defeat electoral reform, he could then secure the Tory majority which eluded him this time. He will have played a shrewd game.

But whether the Liberal Democrats will benefit for their part in this is less clear. They are likely to fight the next election separately, but will still share any blame falling on the government, while maybe getting little credit .

As in the 1979 election, after their pact with Callaghan, they may again get mauled between the two big party beasts. In that situation, Mr Clegg will not be forgiven by his party faithful.

It will all depend on him winning that electoral reform referendum.