TONY BLAIR’S old constituency will disappear under the most dramatic redrawing of Britain’s electoral map for decades, academics suggest.

The Labour stronghold of Sedgefield, County Durham, first created in 1918, is among three North-East seats that will be axed before the next General Election, a study suggests.

The other two most vulnerable constituencies are Labourheld Jarrow, in South Tyneside, and Wansbeck, in North Tyneside, according to Liverpool University researchers.

However, the cull of 50 seats nationwide – demanded by David Cameron to save money – will not deliver the expected Conservative boost in the North-East, the study found.

Because Tory-held Stockton South would include parts of Stockton North, a Labour seat, it is predicted to turn from blue to red – costing the prime minister one of only two seats in the region.

The publication of the Boundary Commission’s recommendations in September is expected to trigger a political row and mutiny in the Coalition.

The analysis has suggested redrawing the map will cost the Lib Dems a quarter of the party’s seats – 14 out of 57.

Yesterday, senior Lib Dem Lord Tyler suggested that MPs will rebel rather than vote through the new electoral map, in 2013.

The study suggests the Tories would lose 16 seats, almost matching Labour’s loss of 17.

Lewis Baston, of the research group Democratic Audit, said his model was based on guidelines set out for the Boundary Commission in legislation.

Suggesting the Tories had misjudged the benefits, he said: “They put too much faith in this. It will unsettle MPs of every party, all over the place.”

Other seats in County Durham are predicted to change little, but the map is tipped to be redrawn so dramatically in east Cleveland, Tyneside and Wearside that seats will require new names.

John Burton, Tony Blair’s former Sedgefield constituency agent, said: “These things come round again and again, and probably in 20 years from now they will be talking about changes again.”