The exceptional hardship scheme, originally proposed under Labour, was subject to a public consultation earlier in the summer.

As a result of feedback, its scope has been extended, although critics argue not by nearly enough.

Under the scheme, the Government will buy properties on the preferred route through Bucks if the owner has a tightly defined pressing need to sell.

Originally it only applied to owner-occupied homes.

But it will now also apply to commercial properties with an annual rateable value not exceeding £34,800, agricultural units, those who have recently inherited a property and people whose property has been repossessed and who urgently need their lender to sell it.

However, the Government has refused to extend the exceptional hardship scheme to include properties along other alternative routes and those along tunnelled sections, which it is argued are shielded against the full impact of HS2.

Hilary Wharf, from the HS2 Action Alliance, which offered its own alternative scheme, said she was 'naturally disappointed that the Government persists with a lightly modified version of their original proposal'.

"This outcome appears to have both ignored our findings and the overwhelming concerns of those consulted.

"While we welcome these changes, they are not sufficient to remedy the scheme's inadequacies."

She said the scheme remains 'irrational and unfair'.

"It seems still to accept some reasons for wanting to move but not others, and seeks to contain qualifying properties to a tight geographical area around route option three."

She said only £15 million has been ringfenced by the Government for the scheme – compared to the £30 billion it is prepared to spend on building the line.

"For a route that is over 200kms this means very few people will benefit," she said.

The scheme will launch on August 20. A consultation on the line will be held next year.