Under the new rules, MPs could face criminal sanctions if they fail to disclose any interests, which Hawkins (pictured) fears might make them reluctant to take part in market research surveys because of the need to officially declare any incentive they get in return. The anonymity that they would usually enjoy as survey respondents could also be at risk, he said.

Hawkins said: “If the rules on outside interests are drawn so tightly that MPs effectively feel unable to take part in market research, it will encourage a return to the dark days of the 1990s when lobbyists like Ian Greer could trade on personal contacts. These new rules will create a wall of secrecy around MPs and thus a premium on inside knowledge, making it far less transparent.”

He told Research that there was currently a “huge amount of confusion” about what the sanctions could be. The fear of being punished for giving incorrect information about incentives, as well as losing their right to anonymity, would “inevitably put MPs off taking part in market research”.

Hawkins added that the legislation, which is due to complete its passage through the House of Commons later today, is being rushed through in a “knee jerk” reaction to the outcry over MPs’ expenses.

“The point is very simple,” he said: “this hasn’t been thought through. If you’re looking for transparency you should be encouraging MPs to take part in market research, not making it difficult for them to to so.”

The ComRes chief, who is appealing against the legislation, said: “I would put this in the same category as the Dangerous Dogs Act and the ban on hand guns. You get the sense that the government wants to be seen to be doing something, even if it is the wrong thing.”