Allegations made about an MP’s “penchant for small boys” were passed to the security service but were not then investigated or reported to police, an inquiry has heard.

The claim concerned Peter Morrison, the Conservative MP for Chester, the wide-ranging Independent Inquiry into Child Sexual Abuse (IICSA) was told.

The Westminster part of the inquiry is expected to sit for three weeks and aims to address “outstanding questions of public concern” related to child abuse allegations.

Lead counsel to the inquiry Brian Altman QC said that during its work the inquiry has obtained a copy of a 1986 letter, written by then-director general of the security service Sir Antony Duff.

Mr Altman said: “The letter makes it clear that the information that Mr Morrison had ‘a penchant for small boys’ had been passed to the security service by a member of the Westminster establishment, who had heard it from two sources.

UK news in pictures Show all 50 1 /50 UK news in pictures UK news in pictures 18 September 2020 A model presents a creation during the Bora Aksu catwalk show at London Fashion Week 2020 Reuters UK news in pictures 17 September 2020 World kickboxing champion Carl Thomas during his attempt to run a marathon while pulling a plane at Elvington Airfield near York. The attempt is raising funds for Ollie's Army Battling Against Battens, an organisation campaigning to raise GBP 250,000 to fund a clinical trial aimed at saving the sight of children with CNL2 Batten Disease PA UK news in pictures 16 September 2020 Labour deputy leader Angela Rayner speaking during Prime Minister's Questions UK Parliament/AFP/Getty UK news in pictures 15 September 2020 People enjoying the autumn sunshine as they punt along the River Cam in Cambridge PA UK news in pictures 14 September 2020 Early morning light bathes the skyscrapers of the City of London, at the start of a week in which the UK is expected to bask in temperatures of more than 30 degrees PA UK news in pictures 13 September 2020 England celebrate after they dismissed Australia's Alex Carey to win the second ODI match of the series at Emirates Old Trafford, Manchester PA UK news in pictures 12 September 2020 Protesters outside BBC Broadcasting House in central London, as marches and rallies form across the country calling for a 15% pay rise for NHS workers and an increase in NHS funding PA UK news in pictures 11 September 2020 An empty migrant dinghy floats off the beach at St Margaret's Bay after the occupants landed from France in Dover Getty UK news in pictures 10 September 2020 A view of small boats thought to be used in migrant crossings across the Channel at a storage facility in Dover, Kent PA UK news in pictures 9 September 2020 EU's chief negotiator Michel Barnier, left, arriving from the Eurostar with EU Ambassador to the UK, Portuguese diplomat Joao Vale de Almeida at St Pancras International railway station, London, for the latest round of the negotiations on a free trade deal between the EU and the UK PA UK news in pictures 8 September 2020 Dawn over Coquet Island, a small island off Amble on the Northumberland coast PA UK news in pictures 7 September 2020 A hovercraft arrives to Southsea, Hampshire from the Isle of Wight PA UK news in pictures 6 September 2020 Forensics officers near the scene of multiple reported stabbings in Birmingham Reuters UK news in pictures 5 September 2020 Anti-migrant protesters demonstrate in Dover against immigration and the journeys made by refugees crossing the Channel to Kent PA UK news in pictures 4 September 2020 Activists take part in a demonstration against the HS2 hi-speed rail line outside the Department of Transport AFP via Getty UK news in pictures 3 September 2020 Peter Baker, who plays Trigger in the musical version of Only Fools and Horses, sweeps the stage of the Theatre Royal Haymarket in London, after observing a 15 minute silence to show solidarity with those in the theatre industry that have lost their jobs due to the coronavirus pandemic PA UK news in pictures 2 September 2020 Kadie Lane, right, 11, and Brooke Howourth, 11, hug on their walk to Marden Bridge Middle School in Whitley Bay, Tyne and Wear, for their first day of term, as schools in England reopen to pupils following the coronavirus lockdown PA UK news in pictures 1 September 2020 Extinction Rebellion protesters sitting outside The Houses of Parliament in Westminster, London PA UK news in pictures 31 August Surfers at Long Sands Beach, Tynemouth PA UK news in pictures 30 August Black Lives Matter protesters march through Notting Hill in London in the first Million People March EPA UK news in pictures 29 August A protester reacts as she demonstrates against the lockdown and use of face masks, amid the coronavirus disease outbreak, outside Downing Street in London Reuters UK news in pictures 28 August Caribbean soca dancers display their costumes as they promote the first ever digital Notting Hill Carnival, following the cancellation of the normal Carnival festivities due to the continued spread of the coronavirus disease, in London Reuters UK news in pictures 27 August Father and son team Chris and Sam Milford from historic building conservation specialists WallWalkers begin restoration work on the spire of Norwich Cathedral, which stands at over 312ft high. The first known spire was completed in 1297 PA UK news in pictures 26 August Giant waves at Seaham in County Durham, as the bad weather continues PA UK news in pictures 25 August An assistant at the Wallace Monument cleans the case which houses the William Wallace sword in the Hall of Arms room at the monument near Stirling as they prepare to re-open PA UK news in pictures 24 August Restored World War Two landing craft LCT 7074 is transported from from the Naval Base in Portsmouth to its final resting place at the D-Day Story at Southsea PA UK news in pictures 23 August Jenny Nguyen and Tony Cao, from Vietnam, pose for wedding photos on Tower Bridge in London, as it remains closed to vehicles after it was stuck open on Saturday due to a "mechanical fault". The landmark's Twitter account confirmed only pedestrians and cyclists could use it on Sunday morning PA UK news in pictures 22 August England's Zak Crawley hit 267, joining the exclusive Double Hundred club, on day two of the Third Test match against Pakistan at the Ageas Bowl, Southampton PA UK news in pictures 21 August Harri Teale gathers lavender during the annual harvest on the Wolds Way Lavender farm near Malton in North Yorkshire PA UK news in pictures 20 August Parents and a student react after checking GCSE results at Ark Academy in London Reuters UK news in pictures 19 August Tate Modern workers hold a strike outside the gallery in London, to protest the institution's announcement that it would cut more than 300 jobs from its commercial arm, Tate Enterprises PA UK news in pictures 18 August Two rescued brown bear cubs, Mish (left) and Lucy, cool off in a pool after arriving at their new home with the wildlife conservation charity Wildwood Trust in Herne Bay, Kent. The orphaned pair, who have been living in a temporary home in Belgium since they were found abandoned and alone in a snowdrift in the Albanian mountains, will be acclimatised to their new life in the country before moving to a permanent home PA UK news in pictures 17 August A level students celebrate outside the Department for Education in London after it was confirmed that candidates in England will be given grades estimated by their teachers, rather than by an algorithm. The government U-turn comes just days after Education Secretary Gavin Williamson vowed there would be "no U-turn, no change. PA UK news in pictures 16 August Wasp players take a knee as Northampton Saints stand prior to kick-off in their Premiership match at Franklin's Gardens PA UK news in pictures 15 August Piper Colour Sergeant Lil Bahadur Gurung attends the VJ Day National Remembrance event, held at the National Memorial Arboretum in Staffordshire, Britain Reuters UK news in pictures 14 August People including students hold placards on Whitehall outside Downing Street as they protest against the downgrading of A-level results. The government faced criticism after education officials downgraded more than a third of pupils' final grades in a system devised after the coronavirus pandemic led to cancelled exams yes AFP via Getty UK news in pictures 13 August Benita Stipp (centre) and Mimi Ferguson (left) react as students at Norwich School receive their A-Level results PA UK news in pictures 12 August 2020 A train derailment near Stonehaven has left three people dead. Driver Brett McCullough, conductor Donald Dinnie, and a passenger were killed when the 6.38am Aberdeen to Glasgow Queen Street service crashed amid heavy rain and flooding BBC UK news in pictures 11 August 2020 A woman hydrates in the sun after open water swimming at the West Reservoir Centre in north London Tolga Akmen/AFP via Getty UK news in pictures 10 August 2020 Prime Minister Boris Johnson takes part in an archery session as he visits Premier Education Summer Camp at Sacred Heart of Mary Girls' in Upminster Reuters UK news in pictures 9 August 2020 People cycle through Cambridge as the heatwave continues in Britain EPA UK news in pictures 8 August 2020 Healthcare workers take part in a protest in London over pay conditions in the NHS Getty UK news in pictures 7 August 2020 Emergency services make their way along the seafront on Bournemouth beach in Dorset on one of the hottest days of the year PA UK news in pictures 6 August 2020 Alison Murphy poses for a picture by husband Peter as she walks through a field of sunflowers in Altrincham, Cheshire PA UK news in pictures 5 August 2020 Pakistan's Abid Ali being bowled by England's Jofra Archer during day one of the First Test match at the Emirates Old Trafford, Manchester PA UK news in pictures 4 August 2020 The 'Timbuktu tumblers' from Kenya perform their balancing act on the Southsea waterfront as Zippos Circus reopens in Portsmouth Rex UK news in pictures 3 August 2020 Pelicans interact with a visitor in St James's Park in London PA UK news in pictures 2 August 2020 Lewis Hamilton drives with a puncture towards the finish line to win the Formula One British Grand Prix at Silverstone POOL/AFP via Getty UK news in pictures 1 August 2020 Arsenal's Pierre-Emerick Aubameyang celebrates with the trophy and teammates after winning the FA Cup, as play resumes behind closed doors following the outbreak of the coronavirus disease Pool via Reuters UK news in pictures 31 July 2020 People enjoy the sunny weather at a Bournemouth Beach Reuters

“We have obtained other documents relevant to this correspondence from both the Cabinet Office and the security service. Those documents make it clear that neither the security service nor the Cabinet Office took steps to investigate this allegation, nor did they report them to the police.”

It was one of a series of matters raised on the opening day of an inquiry, which was earlier branded a “witch hunt against dead politicians”.

The hearing was told the inquiry will not consider allegations made by Carl Beech, previously known as “Nick”, about a Westminster paedophile ring. Mr Beech has since been charged with perverting the course of justice and fraud.

Support free-thinking journalism and attend Independent events

Mr Altman stressed the inquiry will look at how organisations responded to child sex abuse allegations rather than the truth of claims against individuals.

The IICSA has already stated allegations against people accused of wrongdoing during the hearing are not necessarily true.

The probe will look at seven topics during its investigation, including whether political parties turned a blind eye to allegations and if there were attempts to cover up abuse claims.

The Morrison case study will be considered alongside how the Liberal Party, now the Liberal Democrat Party, responded to allegations made against the late MP Sir Cyril Smith and a more recent incident regarding Green Party member David Challenor.

The late Liberal MP Cyril Smith (PA)

The operation of the Whips’ offices in parliament and the existence of so-called “dirt books” containing “scandal” about MPs will also be examined, as will the honours system, following concerns around honours potentially being granted to people accused of abuse either before or after their nominations.

The inquiry will also consider a claim the Paedophile Information Exchange received £30,000 in funding from the Home Office’s then Voluntary Services Unit (VSU), disguised as payment to the Women’s Royal Voluntary Service (WRVS or now RVS).

Mr Altman said a question raised by Labour’s Tom Watson in the House of Commons in 2012, saying there was “clear intelligence suggesting a powerful paedophile network linked to parliament and No 10”, could be seen as the “catalyst for the establishment of this inquiry”.

Labour MP Tom Watson (PA)

But Geoffrey Robertson QC, acting for Harvey Proctor – whose home was raided under the Metropolitan Police’s Operation Midland before the probe closed in 2016 without a single arrest – claimed Mr Watson and “various febrile journalists” had “started a moral panic” over an alleged paedophile ring.

Daniel Janner QC, son of the late Labour peer Lord Janner, who died in 2015 after being found unfit to stand trial over alleged sex offences, claimed the allegations forming part of the probe were based on “tittle tattle, false rumours and dodgy dossiers”.

He said the inquiry was “a witch hunt against dead politicians”.

The hearing was adjourned.