A former anti-slavery commissioner has described the failure to find someone to replace her as “deeply regrettable” and suggested there could be a conflict of interest with the Home Office being in charge of appointing someone to the role.

Dame Sara Thornton left the post – which she said is a key appointment – in April last year and it has been vacant since.

The ex-police chief said she does not know whether the lack of a replacement is deliberate or down to poor administration and bureaucracy.

She was asked during the opening session of the Home Affairs Committee’s new inquiry into human trafficking whether she thinks the failure to make a new appointment is international.

She told the MPs on Wednesday: “I don’t know. I think it’s deeply regrettable.

“Whether it’s deliberate or whether it’s just poor administration and poor bureaucracy, I don’t know.

“But, given the level of public discourse about modern slavery, given that we had the Illegal Migration Bill and also lots of issues about implementation of the Nationality and Borders Act, it seems to me that this is a key appointment and Parliament surely should be informed by the expert views of an independent slavery commissioner.”

She suggested recruitment to the role should be overseen by the Cabinet Office rather than the Home Office, and that it should be for a longer term.

She said: “I do think potentially the Home Office has a conflict of interest. I also think that a three-year appointment for this sort of role is not long enough – it needs to be five or seven years so that a commissioner can act without fear or favour.”

Baroness Butler-Sloss said the fact that the role has been vacant for a year ‘adds huge weight to the fact the Home Office should not be appointing the anti-slavery commissioner’ (Stefan Rousseau/PA)

Baroness Butler-Sloss, a former senior judge and independent crossbench peer, said Dame Sara had been “outstanding” in the role.

“It’s inconceivable that if this had been a totally objective approach to who should be appointed, that she wasn’t reappointed, and it seems to me that lies exactly in the fact that the Home Office has control.”

She said the fact that the role has been vacant for a year “adds huge weight to the fact the Home Office should not be appointing the anti-slavery commissioner”.

The role was created under the Modern Slavery Act 2015 and involves the commissioner giving independent advice on modern slavery issues and how they should be addressed.

According to the Government website, the commissioner’s role includes encouraging good practice to increase the identification and protection of victims of modern slavery, and ensuring victims and survivors in the UK are supported.

It also involves enabling effective prevention of slavery and human trafficking offences and promoting an improved law enforcement and criminal justice response to modern slavery across the UK.