David Heath: The sooner we get rid of all these fiddlers and freeloaders, the better

How could any MP think it was right to hire themselves out to private companies "like a cab" as one so charmingly put it, as if even the most avaricious taxi driver would ever charge thousands of pounds for a few hours work?

How could anyone be so oblivious of the "cash for questions" scandals that so ensnared the previous Conservative government? How could they value their reputation so cheaply and their "influence" so highly?

I'll tell you how. Greed. Cashing in. Grabbing the money now while someone still remembers that they used to be the Secretary of State for something. And it stinks to high heaven.

I don't frankly care whether it was within the letter of the rules or not. Working as an MP is, in my book, a full-time job. Yes, I know some people think it's important they keep up their former profession or business interests at the same time, and some even make a virtue out of it.

I'm not convinced, but then I take the old-fashioned view that the job means attending the House of Commons and speaking up for constituents.

And that's the point. Speaking up for constituents, or at least the common good of the national interest. Not the financial interests of whichever company has hired them to promote them. Not the short-term advantages of a lobby company or a public relations man. And how about the amounts involved? Five thousand pounds a day? So, in a couple of days, these fine upstanding Parliamentarians can earn more than a pensioner gets in a whole year? And that's on top of an MP's salary and a very comfortable Ministerial pension. What on earth do their constituents make of that?

What upsets me even more is that Parliament always wakes up to these things after the event. We did it with expenses. When some of us were arguing for changes in the system to tighten up the rules and increase transparency long before the expenses scandal hit the headlines, the "good old boys", led by the then Speaker, made sure nothing was done.

When that particular scandal broke, no one came out of it looking good. But I am proud not only that I and my Liberal Democrat colleagues fought the vested interests protecting the status quo from the Labour and Tory benches, but that no Lib Dems were among the second home "flippers" and Capital Gains Tax dodgers that were guilty of the most abhorrent abuses.

When Liberal Democrats tried a year or so ago to put an end to the influence of the big donors, so corrosive to the political process, then those who had the biggest vested interests made sure there was no progress. Now, with lobbying, we had a select committee of Parliament recommending tightening up the rules, but the Government did nothing. And when Liberal Democrats suggested amendments to the Companies Act two or three years ago to require companies to publicly expose their lobbying activities to scrutiny, they were blocked.

As usual, nothing is done until it is too late.

I don't know whether the ex-Ministers involved in this latest expos actually did have any effect on government policy. The Transport Secretary Andrew Adonis says not with regard to National Express and the premature ending of its East Coast Main Line franchise, and he is someone whose word I tend to accept.

But the Government could reassure everyone by releasing all the notes of meetings, letters or e-mails between Ministers and the would-be lobbyists so we can judge for ourselves. They won't. They could change the ministerial code, as I suggested on Monday, so that neither

Ministers nor civil servants would meet and discuss matters of detailed policy if there is any possibility that the MP is being paid for by a commercial interest to raise the issue. They won't.

Meanwhile, the reputation of politics, and the many decent people, still, who think it's important that the laws of this land are made conscientiously and without partiality, that local communities are properly represented and government held to account on behalf of all of us, is dragged through the mud yet again.

As I said, I'm sick and tired of them all. The sooner we get rid of the fiddlers and the freeloaders, the better.

David Heath MP is the Liberal Democrat Shadow Leader of the House.