DR Evan Harris blamed “inflamatory” leaflet campaigns for his being ousted from parliament last week.

The Liberal Democrat MP lost his Oxford West and Abingdon seat after 13 years when Conservative Nicola Blackwood beat him by just 176 votes.

Dr Harris said he feared campaigns by an animal rights group and an Anglican priest played a part in swinging votes against him.

He said: “There were leaflets from the animal rights group that were both inflamatory and defamatory.

“Who knows how many people might have thought ‘there must be something in this’? It went everywhere.

“There was a second leaflet, which we think was distributed by a right wing Christian group. It was not quite as inflammatory, but it was misrepresentative.

“A smear only becomes effective if some people believe it. You cannot ignore negative attitudes like this because they just grow.”

Dr Harris said he was aware he was recognised as a politician who had taken strong positions on ethical issues.

He said: “I have campaigned mainly on the NHS, education and public services. But I have taken a stand on some of the most controversial ethical issues that have divided people 50-50.

“I hope that this does not discourage other politicians from speaking out on some of these important issues.

“If people think these kind of negative campaigns are effective, we could see more of it. But we need politicians who speak their minds. You cannot agree with both sides. Some politicians keep quiet and do not argue their case.

“In the end, politics is not about winning and losing. It is also about campaigning on issues, and I am pleased I have a record on that.”

Rev Lynda Rose, who produced leaflets highlighting the MP’s voting record on ethical issues, said: “There is no big extremist group lurking around. The leaflet we put out was purely factual.

“It wasn’t inflammatory at all and I don’t think it was the slightest bit misrepresentative.”

Two leaflets circulating in the constituency contained references to reports Dr Harris had been labelled ‘Dr Death’ because of his views on animal testing.

Animal Protection Party candidate Keith Mann, who spent seven years behind bars for arson attacks on slaughterhouse lorries in the early 1990s, said: “I am not concerned about gaining votes. I was concerned about taking votes off Evan Harris and seeing him lose his power base.”

He added: “If Evan Harris has got a problem with anything we have said about him, we will debate it in court quite happily.”

Mr Mann received 143 votes.

Dr Harris said he hoped to regain the seat for the Lib Dems. He said other factors which contributed to the result included a well-funded Conservative campaign. He added that he had always regarded the seat as marginal.