Both entered politics with a desire to improve things for Britain. Both achieved political success, Heath becoming Prime Minister, and Benn Minister for Trade and Industry. Both then returned to the back benches, from where they have spoken passionately on occasion on issues that they genuinely believe in, often in defiance of their own parties. One aspect of the charge could be that politicians want to get rich quick. One would be better off as an civil servant.
Nobody goes into politics to get wealthy.
In the current climate, when political sleaze is a such a major issue, the penalties for the smallest misdemeanour are severe. Financial misdeeds are particularly damaging, and party machines move rapidly to expel wrongdoers, such as Peter Mandelson, who left Government immediately after the affair of his dubious mortgage application became known. Those who do so would be seriously deluded. This isn't to say that there are not some huge and unpleasant egos in the House, or that people are not ambitious or wish to get promoted. Of course they do.