Bungling Scotland Yard detectives in charge of the VIP sex abuse inquiry became so fixated with appeasing Tom Watson they failed to spot the accuser was a serial liar, a damning report will conclude.

Such was the influence the Labour MP wielded over the Metropolitan Police, that one officer even described the need to keep him on side as a "priority".

Sir Richard Henriques's report into the disastrous Operation Midland investigation, is due to be published on Friday following weeks of intense pressure.

It will identify 43 separate failings by the Metropolitan Police, including the decision by Detective Superintendent Kenny McDonald to describe Beech's outrageous allegations as "credible and true".

The retired High Court judge will also be highly critical of those officers who he accuses of carrying out "illegal raids" on the homes of some of those accused, including Lord Brittan, Lord Bramall and Harvey Proctor.