Prof Wadhams said that in the weeks after Prof Laxon’s death he believed he was targeted by a lorry which tried to force him off the road. He reported the incident to the police.
Asked if he thought hitmen might have been behind the deaths, Prof Wadhams, who is Professor of ocean physics at Cambridge University, told The Telegraph: “Yes. I do believe assassins possibly murdered them but I can see that I would be thought of as a looney for believing this.
"But it’s just very odd coincidence that something like that should happen in such a brief period of time.”
He added: “They [the deaths] were accidents as far as anybody was able to tell but the fact they were clustered like that looked so weird.”
Asked who might have wanted them out the way, he replied: “I can only think of the oil lobby but I don’t think the oil lobby goes around killing people.”
He admitted it would have been "stupid" to go to the police with his concerns over the three deaths, not least because he was "suspicious" of the authorities - he cited the example of the death of the government’s weapons expert Dr David Kelly.
David Kelly (Reuters)
Prof Wadhams added: “I thought if it was somebody assassinating them could it be one of our people doing it and that would be even more frightening. I thought it would be better not to touch this with a barge pole.”
His suspicions drew outrage on Saturday from Prof Laxon’s partner, who was also a close friend of Dr Giles. When told what Prof Wadhams had said, Fiona Strawbridge, head of e-Learning at UCL, replied: “Good god. All of this is completely outrageous and very distressing.”
The couple had been staying in a friends’ converted mill in the Essex countryside when her partner fell down the stairs in the early hours of New Year’s Day. He died the next day from head injuries.
“It was very steep stairs and I heard Seymour fall,” said Ms Strawbridge, “It is just completely bonkers [to suggest murder].
"I am sure there are some climate scientists who do get trolled and pursued but Seymour wasn’t one of them. I would have known if anybody had been pursuing him.
“Sometimes there are tragic coincidences and you have to accept that.”