Jeremy Corbyn has defended his decision to hire a former Sinn Fein staffer who worked for Gerry Adams and has links to convicted IRA terrorists.

Jayne Fisher, who was head of Sinn Fein's London office, is due to start working in the Labour leader's office in January.

The move to hand such a key role to someone with such strong links to the controversial hard-left Irish nationalist party has caused fury among Labour MPs, who said it would further undermine the party’s reputation on national security.

Last night they confronted Mr Corbyn over the appointment, but he insisted Ms Fisher was ‘very lovely… and will be a great appointment’.

Today a video emerged of Ms Fisher singing on stage alongside the infamous Brendan ‘Bik’ McFarlane in 2009.

Today a picture emerged of Jayne Fisher, pictured second right, sitting alongside Sinn Fein MLA Jennifer McCann, pictured second left, who was jailed for ten years for shooting a police officer

Jeremy Corbyn has hired Jayne Fisher, who was head of Sinn Fein's London office. Ms Fisher is pictured far left at a meeting with Mr Corbyn, pictured third left, Sinn Fein's deputy First Minister and Sinn Fein's president Gerry Adams, second right, during a meeting in Parliament last year

He was an IRA member who was handed a life sentence for his role in the bombing and machine gun attack on a Belfast bar in 1975, which killed five people.

The Guido Fawkes website also revealed photos of Ms Fisher alongside Sinn Fein MLA Jennifer McCann, who was jailed for ten years for shooting a police officer, and another photo of her sitting next to Sinn Fein’s Conor Murphy, who was sentenced to five years in prison for explosives in 1982.

MailOnline has contacted Ms Fisher for comment but has not received a response.

Ms Fisher will be in charge of 'stakeholder engagement' for the Labour leader when she joins next month.

The appointment also risks further antagonising the Jewish community due to her anti-Israel history. In a rally in Hyde Park in 2014 she helped spread Mr Adams' call for the 'expulsion' of Israel's ambassador in Dublin.

One Labour MP who confronted Mr Corbyn over the appointment last night told PoliticsHome: 'It's fair to say that the general response was one of shock and anger.

'Obviously, we really need to annoy more people in the run-up to Christmas.

'Jeremy said she was very lovely and very good and will be a great appointment. But she's worked for the Shinners - there's no getting round that.'

Today a video emerged of Ms Fisher singing on stage alongside the infamous Brendan ‘Bik’ McFarlane in 2009

Another photo showed Jayne Fisher, circled, sitting next to Sinn Fein’s Conor Murphy, also circled, left, who was sentenced to five years in prison for explosives in 1982

Ms Fisher has written regularly about the IRA's important role in history, writing in a blog post in 2011 that the 1981 Hunger Strike was 'one of the most important and courageous struggles to have taken place anywhere in history, anywhere in the world'.

Mr Corbyn has gone on a hiring spree with the extra cash flowing in from the trade unions.

But Labour insiders acted with dismay when they discovered he was using part of the funds to take on a former staff member of Mr Adams.

Ms Fisher simply describes herself as a 'London based socialist' on Twitter and is part of the TUC's international committee.

She stood in for the former militant, Mr Adams, at a Hyde Park rally for Gaza in 2014 to deliver his speech, calling for the Israeli ambassador to Ireland to be expelled.

In 2012, Mr Adams urged his Twitter followers to sponsor Miss Fisher's charity cycle ride around Cuba. He said: 'Will u sponsor Jayne Fisher's Cuba Cycle Challenge appeal for the Music Fund for Cuba. In memory of Kirsty McColl.'

She has been pictured with Mr Corbyn and her former boss, Mr Adams, in an infamous cosy picture taken in the Houses of Parliament.

The latest register of MPs' staff – updated on November 8 this year – lists her as working for Paul Maskey, the MP for Belfast West.

Jeremy Corbyn and Gerry Adams are long-standing friends. In 1996, Mr Corbyn was accused of 'traitorous' behaviour for helping Sinn Fein boss Gerry Adams plug his autobiography inside the Houses of Parliament

But a woman who answered Mr Maskey's constituency office phone in Northern Ireland confirmed she was no longer working for the party and had left her post 'some time over the summer'.

Miss Fisher has posted thousands of Tweets but has deleted all but the last few days' worth.

Her latest one is to publicise a branch meeting of the Labour party in the Marx Library in Clerkenwell, London.

Another Tweet this week praised the Labour London Mayor: 'Good to see @SadiqKhan re-assert the strong commitment to London St Patrick's events & acknowledge Irish community.'

Sinn Fein has four MPs at Westminster but none of them can take up their seats as they refuse to pledge allegiance to the Queen.

Labour Party rules stipulate that you cannot be a member of any other party but there is no time period that must pass between joining and quitting another party.

Miss Fisher, who turned 50 this October, lives in Islington in a council flat with Mike Hedges, a 57 year-old who chairs Unite's London and Eastern Political Committee and is a Labour member.

Mr Hedge is a taxi driver who drove Mr Corbyn around the capital when he was elected leader. One photo shows Mr Corbyn and Miss Fisher in the back of his car.

A Labour MP, who did not wish to be named, slammed Jeremy Corbyn, pictured at Prime Minister's Questions today, over the appointment of Jayne Fisher. They said: 'This is just the latest example of an ill-judged appointment of someone who doesn't share Labour values'

A Labour MP, who did not wish to be named, said: 'This is just the latest example of an ill-judged appointment of someone who doesn't share Labour values.

'It could also go down badly amongst all those voters who are nervous about the Labour leadership's commitment to national security given previous allegiances.'

Another Labour source said: 'Jayne has been in and around Corbyn's office for months. She is finally taking up a more permanent role.'

The source said there were concerns about her appointment as she was a member of the Socialist Action Group, the hard left, secretive faction that moderates believe has been destabilising the Labour Party.

Mr Corbyn caused outrage in the weeks after the 1984 Brighton bombing by inviting Gerry Adams and other Sinn Fein members to the Houses of Parliament.

A spokesman for Mr Corbyn said: 'We don't comment on staffing matters'.

Miss Fisher did not return phone calls or texts when asked for a response.

A Labour source said that Miss Fisher had first joined the Labour party at 18 and has been involved with its women's conference and the Labour Party Irish Society.

She became involved with Sinn Fein after taking part in a cross-party movement, the 'Friends of Good Friday Agreement'.

'That's how she ended up working for the Sinn Fein parliamentary group. As part of the peace process, they wanted a presence in Westminster,' one insider said.