The political establishment spent decades turning "a blind eye" to allegations of child sexual abuse, with high-profile politicians such as former Chester MP Peter Morrison protected from police action as whips sought to avoid "gossip and scandal" which would damage the parties, a scathing report has found.

The long-awaited investigation into historical allegations against MPs, peers and civil servants working in Westminster found political institutions "significantly failed in their responses to allegations of child sexual abuse".

It cited as an example the evidence of former Liberal party leader Lord Steel, who told the Independent Inquiry into Child Sexual Abuse (IICSA) last year how he failed to pass on allegations against prominent colleague Sir Cyril Smith, even though he believed them to be true, because it was "past history".

He later recommended Smith for a knighthood.

The report found no evidence of a co-ordinated "paedophile ring" in Westminster, following claims by fantasist Carl Beech of its existence, and also stated there was no proof such a network was covered up by security services or police.

But it said institutions "regularly put their own reputations or political interests before child protection".

Professor Alexis Jay, who chaired the inquiry, said: "It is clear to see that Westminster institutions have repeatedly failed to deal with allegations of child sexual abuse, from turning a blind eye to actively shielding abusers.

"A consistent pattern emerged of failures to put the welfare of children above political status although we have found no evidence of an organised network of paedophiles within government.

"We hope this report and its recommendations will lead political institutions to prioritise the needs and safety of vulnerable children."

The report identified how former prime minister Margaret Thatcher and ex-Conservative party chairman Norman (now Lord) Tebbit were aware of rumours about Peter Morrison – City of Chester MP between 1974 and 1992 – having "a penchant for small boys" but did nothing about it.

The report said the allegations "should have rung alarm bells in government".

But, instead, "considerations of political embarrassment and the risk to security were paramount, while the activities of an alleged child sexual abuser who held senior positions in government and the Conservative Party were deliberately overlooked, as was the course of public justice".

Indeed, the inquiry found there was a "consistent culture for years" in the whips' offices to "protect the image" of their party by "playing down rumours and protecting politicians from gossip or scandal at all costs".

It meant victims' interests were often overlooked, with many organisations failing to pass on allegations to police.

The report said Gyles Brandreth, who succeeded Morrison to become Conservative MP for Chester in 1992, described being told that Peter Morrison was a monster who interfered with children, although he went on to describe these allegations as “slurs”.

The report states: "Efforts were made to suppress these rumours rather than conduct any more formal investigation. The local agent for the Conservatives, Frances Mowatt, organised a meeting with her counterpart in the Labour Party prior to the 1987 general election to prevent allegations against Peter Morrison being used in the campaign, promising that Morrison would stand down next time.

"At the Inquiry hearing Mrs Mowatt denied that this meeting ever took place, but a letter dated 7 July 1987 from the Security Services to the then Cabinet Secretary, Sir Robert Armstrong, in effect confirmed the existence of that meeting and broadly what was discussed. Mrs Mowatt was less than frank by concealing what was an attempt by her to cover up for Peter Morrison in 1987.

"Whether there was an ongoing pact between local Labour and Conservative parties not to mention Peter Morrison’s behaviour during his time as MP is debatable and was subject to conflicting evidence throughout the Inquiry hearing.

"There was also some suggestion that the authorities had become involved in a cover-up. Allegations were made that the local police had suppressed charges following the incident on the train at Crewe after a phone call from the Prime Minister’s office and that Peter Morrison was subsequently cautioned by the police, but the record had been expunged from the system.

"The oral evidence of political campaigners provided only limited evidence that political parties secretly conspired and that the police were willing participants in a cover-up, and there is very little documentary evidence that assists.

"What is clear, however, is that despite the seriousness of the rumours and the alleged incident on the train at Crewe, no-one considered the potential fate of children; the focus of attention remained unswervingly on political consequences rather than the welfare of the child."

It added while it was unclear that the then-PM Margaret Thatcher knew about Peter Morrison being 'a danger to children', senior officials had been made aware.

The report stated it did not occur to anyone at the time that Peter Morrison should be reported to the police.

The report also found senior diplomat Sir Peter Hayman was the beneficiary of "preferential, differential and unduly deferential treatment" over claims he sent obscene material in the post, following a meeting between his solicitor and the then-director of public prosecutions.

There was also "striking evidence" of how "wealth and social status insulated perpetrators of child sexual abuse" from being brought to justice, as in the case of Tory MP Victor Montagu.

The report stated: "A consistent pattern that has emerged from the evidence we have heard is a failure by almost every institution to put the needs and safety of children who have survived sexual abuse first."

The report made a number of suggestions including changes to the Honours system, re-examining the policy over posthumous forfeiture of honours - which would strip knighthoods from the likes of disgraced entertainer Jimmy Savile, and creating widespread and well-understood whistleblowing policies for all Westminster institutions.

The Government has also been urged to review its child safeguarding policies, and for all legitimate political parties to have a "comprehensive safeguarding policy" overseen by the watchdog.