Since then it has grown as tall as the house and blocked sunlight.

But of greater concern, says Bill, 67, is the damage he believes its roots are causing to the house.

Mr Norman said: "There is a large crack under the bay windows on the front of the house. Every time we plaster over it, the crack reappears within a few months. We've asked the council to remove the tree but so far it has been like banging our heard against a brick wall.

"Their answer is for us to dig up own front garden and find out what the problem is, but there's no way we can afford to do that."

Alan Crawley, a campaigner for the former Croydon Central MP Andrew Pelling, has taken up the pensioners' cause. He said: "These things aren't meant to be placed beside houses because their roots rip apart pavements with ease." A council spokesman said: "With regards to any possible damage to the property, we can't find any record of having been contacted about this.

"The advice we always give is that if people do suspect that any structural issues they have may be associated with street trees then they should contact their insurers in the first instance.

"They will investigate and if they do find evidence that a tree is the 'root cause' then they will take this up with us direct."