Margaret Thatcher suprised us in a way that stayed with me all my life

Aged eight, Dominic Prince's dream came true thanks to his local MP

Hands of time: A clock mechanic in Big Ben, a place the public needs special permission to visit (Rex Features)

As an eight-year-old schoolboy, I had a somewhat quirky desire to visit Big Ben and I wanted to look out through the clock face over London. There was only one problem: it wasn't open to the public.

I was told by my mother to write to our local MP, one Mrs Thatcher, then on the back benches of the Opposition. My mother's political affiliations were clear. She was not a supporter, and her sympathies were with the Labour Party, a position she made no secret of.

With not a great deal of hope, I wrote to Mrs Thatcher, who swiftly replied saying that she would be delighted to arrange a visit for myself, my brother and a phalanx of friends, all under the age of nine. After further correspondence, a date and a time was arrived at and we were told to present ourselves to an official at Westminster one morning during the Easter holidays.

It was joyful affair, with us wide-eyed children climbing the 334 steps to the top of the building and being deafened by Big Ben in action. The panoramic view had us glued, we had photographs taken in the clock face. Aged eight, none of us really had much of an idea what an MP was. All we knew was that Mrs Thatcher had fixed it for all of us and that she was frightfully important because she had very posh writing paper.

That might have been that, but when we arrived home my mother sat us all down and told us to write to Mrs Thatcher and thank her for arranging our trip.

We were of no use to her electorally. Did she perhaps think that she could sway our parents to vote for her the following year? I doubt that very much, and anyway she could have had little doubt about my mother's political leanings.

We all regarded the chapter as having come to an end. But a few days later, I received a hand-written note from her on House of Commons notepaper thanking me for thanking her. It read;

"Dear Dominic, Thank you for your letter. It was very nice of you to write to me. I am so glad that you enjoyed seeing Big Ben. It is much bigger than it looks, isn't it? My children have always enjoyed walking round it – except for the climb up the stairs. Yours sincerely Margaret Thatcher (Mrs)."

She wrote similar letters to all my friends. I say similar because they were all different, telling a different story to each of us. I often wondered about her motivation and, as a low-minded journalist, I am still wondering.

In a similarly sceptical vein, I had some nagging doubt about her children having visited Big Ben, but as I had no way of establishing the truth it went to the back of my mind. Nevertheless I treasured the letter, and in my teens I had it framed, and now it peers down at me in my office.

Several years ago, I wrote to our local Labour MP, Martin Linton, telling him how much I had enjoyed my trip and enquiring whether he could arrange the same for my children. I didn't even receive a reply. And about a year ago, for some bizarre reason, I found myself at a lunch with Mark Thatcher. I asked if it were true that he and his sister, Carol, used to visit Big Ben. In a sort of sullen, graceless way, he confirmed that it was, but went on to say: "But of course you couldn't visit nowadays; it's been banned by the bloody health and safety."

He was nearly right. Visits are still undertaken, but you have to be over 11 to attend.

I don't know what the story tells us, except that maybe people don't always fit into the boxes it is convenient to place them in. There is, though, one final act to the story. According to collectors of Thatcher memorabilia, the letter is now worth around £1,000.