(Adds Cameron spokesman)
LONDON, Jan 14 (Reuters) - A senior British minister suggested on Thursday he could campaign to leave the EU if the bloc failed to meet Prime Minister David Cameron's "demands for change", in one of the strongest criticisms of the bloc from a cabinet member.
In a carefully worded article for the Telegraph newspaper, Chris Grayling, the leader of the House of Commons lower chamber of parliament, said the European Union was heading towards further integration that Britain should not follow.
A Cameron ally, Grayling did not say outright that he would campaign to leave the 28-member bloc after the prime minister's renegotiation of Britain's relationship with the EU, but he outlined what he described as his "strong Eurosceptic views".
"Simply staying in the EU with our current terms of membership unchanged would be disastrous for Britain," Grayling wrote.
"I have always believed that it is imperative that his renegotiation takes place and delivers as much potential change as possible ... I want Britain to choose between a changed relationship and leaving."
Cameron's spokesman said the British leader was "relaxed" about the article, which he was aware was being written.
"He (Grayling) has set out that there are clear problems with the status quo in terms of the relationship that we have with the EU, and that is exactly the position the prime minister has taken," he told reporters.
Cameron wants to reform Britain's ties with the bloc before a referendum which he has promised will come by the end of 2017 and says he will campaign to stay in the EU if he succeeds in getting what he calls 'the best deal for Britain'.
The prime minister has suggested he wants the referendum to take place this year, possibly in June at the earliest, and has expressed confidence he can secure change in the four areas where he is seeking to redefine Britain's membership terms.
But some of his closest advisers and dozens of lawmakers in the ruling Conservative Party have indicated that they are not convinced the renegotiation will bring the change they want and have suggested they will vote to leave the European Union.
Earlier this month, Cameron bowed to pressure to allow government ministers to campaign to leave the EU once talks had been completed, heading off the prospect of multiple resignations from his top team.
(Reporting By Costas Pitas and Kylie MacLellan; Editing by Stephen Addison)
Our Standards: The Thomson Reuters Trust Principles.