As there is about to be a general election in which (for the first time during the last quarter of a century) I will not be standing, my time as Member of Parliament for West Dorset has drawn to a close.

One of the effects is that this is the last time I shall be writing this column.

Of course, MPs come and go — and life goes on in their constituencies in much the same way regardless of their appearances and disappearances.

The same, evidently, is true in Parliament itself — where each MP is just 1/650th of the whole. The people enter the Palace of Westminster when sent there by their constituents, and then leave it again either by their own choice or by the choice of their constituents a number of years later; but the institution remains as a far greater thing than the sum of its evanescant inhabitants.

All of this prompts me to reflect on the uncomfortable question: what, really is a Member of Parliament?

Negative answers abound. A Member of Parliament, unless he or she becomes a Minister (and even then only really if he or she is a senior Cabinet Minister close to the centre of the governmental machine) has no executive or administrative authority. Any police officer or traffic warden has very much more immediate power than a Member of Parliament.

And even if an MP could be said to have any significant effect on legislation as a result of casting one of the 650 votes when new laws are being considered, this is entirely at the national level. Locally, unlike a Councillor or a senior Council official, a Member of Parliament has no direct effect on the way things are administered.

Against this background of things that an MP cannot do, it is reasonable to ask what an MP can do — in particular in their own constituency. I have come to the conclusion that there are essentially just two things a constituency MP can achieve: he or she can obtain access on behalf of constituents to people with real power; and he or she can bring together people who would not otherwise engage with one another.

It may not sound like much — but access to the right people, and getting the right people together with one another, can very often lead to the resolution of problems which would otherwise remain unresolved.

Doing that is the one great satisfaction that makes the job of a constituency MP worthwhile.