BORIS Johnson said HS2 campaigners are pretending they are objecting to the project on environmental grounds when they're actually more worried about the effect it will have on house prices.

The Mayor of London said in an interview with Total Politics magazine those opposed to the scheme weren't concerned "the great crested grebe is going to be invaded or whatever".

The planned route of the line will go through the Chilterns Area of Outstanding Natural Beauty and several hectares of designated ancient woodlands, which are more than 400 years old.

He spoke before a debate in Parliament yesterday, where MPs voted in favour of progressing the scheme.

Mr Johnson said: "People are in the humiliating position of having to pretend that there’s some environmental objection that they have, that the great crested grebe is going to be invaded or whatever. What they care about is their house prices.

"It's tragic we have protest groups talking about ‘this ancient woodland’ when actually there’s no tree in this country that’s more than 200 years old. Most mature trees die at about the age of my age, the average life expectancy of a tree can’t be more than about 60 years. There aren’t that many ancient woodlands around is the point I’m trying to make.

"It’s b******s. They’re not campaigning for forests, they’re not campaigning for butterflies. They pretend to be obviously, but what they’re really furious about is that their house prices are getting it."