John White, a Pentagon appointee in the Clinton and Carter administrations, said the e-mail suggests an "unprecedented" level of involvement by senior Pentagon officials in the awarding of contracts.

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Asked in an e-mail whether that conversation in 1980 occurred the way that Carter recounted, Gingrich spokesman Hammond did not respond.

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Paul Carter, leader of Kent's council, has also set up an e-petition calling for the cap to be in place by 2015.

BBC: Paul Carter