It’s dangerous, in my line of work, to promise you’ll be anywhere by 8 p.m. I made this mistake recently, saying I’d turn up to a dinner after a Budget discussion — a ‘quad’ meeting, where I sit with the Prime Minister, George Osborne and Nick Clegg. We’ve been doing this for five years, so have come to know each other pretty well. Not that we all agree; on the night in question, Nick was angry about something (I won’t say what) and our meeting ran on. I headed back with him to Dover House, a magnificent building where I was based during my tenure as Scottish Secretary. A great job: I enjoyed each of the 17 days I spent in it.

The dinner, organised by the Lib Dems, was fun. Some guests made kind remarks about my role in repairing the economy. One seemed particularly quiet, so I tried to include him in the conversation, and at the end thanked him for supporting one of our candidates. I remember wondering how on earth he coped when he seemed to know so little about the business he said he ran. He asked for a photo with me, then I headed home to more phone calls and a red box.

Later, I found out he was an undercover reporter for the Daily Telegraph. I had been caught red-handed thanking supporters for their help. A guest was quoted warning the reporter that I’m not keen on making any more cuts to the 45p tax rate. So I stand exposed — saying the same things about my role in government in private that I do in public. I must have disappointed those who expect something else from politicians. I also must have disappointed the Telegraph; I imagine it takes months to set up such sting, and I feel I rather let them down with my general say-what-you-think LibDemmery.

When the Telegraph story broke, I was in the Highlands and counting my blessings that I represent the most beautiful constituency in the country. I drove from my surgery in Aviemore to attend a pensioners’ lunch at a church in Nairn (home town of the editor of this magazine). The journey across Dava Moor is as beautiful as any you’ll find in the Highlands. At first, the sky was grey. You could still see snow patches by the roadside. When the descent to Nairn began, the sun burst through. I wondered if I could get away with cancelling my plans and going for a walk. Before I entered parliament, I worked for the Cairngorms National Park and had plenty of excuses to stretch my legs and clear my mind. Even now, there’s no better way to escape the political frenzy. A friend from the Cairngorm mountain rescue used to tell walkers thinking of setting off in bad weather that they should ‘remember the mountain will be there tomorrow — just make sure you are’. My sentiments for the election precisely.

I met lots of supporters in Nairn, and others who said they will vote for me this time because they like having a high-profile voice for the Highlands. Or because they want to stop the nationalists. The polls show how high the stakes are for Scotland in the next election. I am biased, but doesn’t this make a clear case for the many Spectator readers in Scotland to support the UK by lending their vote to the Liberal Democrats? One lady told me she voted ‘yes’ in the referendum but will vote for me because of the work I’ve done locally. Very gratifying, but sadly you can’t talk to every voter. Although we do try.

It was my turn to walk the girls to school on Friday: Red Nose Day. Sadly, my younger daughter missed out because she had chicken pox. But the older one wore her red nose and I carried the tin of goodies she made for their bake-off. They were ‘unicorn poop cookies’ — made from multi-coloured dough and baked into a shape not usually associated with food. I decided against bringing some in to the Treasury. There is enough poop in Westminster already.

Then came another night away from home, in Liverpool for the Lib Dem spring conference. No chance to explore the city: party conferences mean lots of time locked in soulless conference centres and hotels. I’ve put it on my list for a return visit. I had to leave early to put the finishing touches to the Budget. It’s the first time I’ve missed Nick’s conference speech — but in rehearsal it was a barnstormer. Or so we told him.

Why are MPs so mean to Julian Huppert? He is sometimes jeered when he stands up to speak in the Commons, perhaps because he is interested in science and introducing facts into debates. I met him in Cambridge for a visit to the site of the new Papworth hospital, whose bid for funding I navigated through the Treasury. Huppert may have unfashionable interests, but he’s a hard working, sincere and effective local MP. Isn’t that what matters? Like all of us, he’ll find out on 7 May.