A controversial book by one of the Portuguese policemen who worked on the Madeleine McCann inquiry has gone on sale.

Former detective Goncalo Amaral was removed from the inquiry last October after criticising British officers.

His book makes fresh allegations about Kate and Gerry McCann who were formally cleared of involvement in Madeleine's disappearance when prosecutors lifted their status as "arguidos" on Monday.

The McCanns have already consulted lawyers after extracts of the book, The Truth Of The Lie, were printed in the Portuguese paper Correio da Manha.

Family spokesman Clarence Mitchell said: "Mr Amaral will face immediate and swift legal action if he in any way implies, either directly or indirectly, that Kate and Gerry were involved in the disappearance or harming of their daughter.

"Beyond that I will not comment. The lawyers will be studying Mr Amaral's book as a matter of some urgency."

In his book, Mr Amaral claims British police held back a potentially important lead for six months.

He wrote that a serious allegation was passed on to Leicestershire Police on May 16 2007, less than a fortnight after Madeleine disappeared.

But he alleged that the UK force did not communicate the information to their Portuguese counterparts until after he was removed from the case in October.

Mr Amaral wrote: "This raises a legitimate question: why did the British police apparently hide that witness statement for six months?"

Leicestershire Police declined to comment on the allegation.

Madeleine was nearly four when she vanished from her family's holiday apartment in the Algarve resort of Praia da Luz on May 3 last year as her parents dined with friends nearby.

Despite a huge police investigation and massive coverage in the Portuguese and British media, she has not been found.

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