COVENTRY Building Society is understood to be preparing a major campaign to get the public to back its plans to take over Northern Rock.

The UK’s third biggest building society has reportedly already carried out a secret poll to see whether people would support it merging with the ‘good’ part of the Newcastle-based state-owned bank. The private survey is said to have been positive.

The Midlands-based mutual, which merged with the Stroud and Swindon building society last year, confirmed last month that it would be interested in taking the Rock back to its roots as a building society.

It said at the time: “Coventry Building Society’s commitment to mutuality has helped deliver consistently superior financial performance and member value throughout the financial crisis.

“The board believes that these credentials would benefit Northern Rock customers if it were to be remutualised as part of Coventry Building Society.”

Today’s reports suggest that the Coventry would need around £200m in new capital to do a deal. It also said to be preparing to lobby politicians and to talk to the Rock’s board about its ambitions.

Northern Rock had no comment on the latest speculation but a spokeswoman said this morning: “We have appointed Deutsche Bank as our financial advisors to assist us in assessing the options to return Northern Rock to the private sector, when a proposition is reached that is in taxpayers best interests.

“All options are currently being explored.”