The BBC is facing a backlash against what are said to be false claims to be aired by Panorama that British taxpayers’ money intended for the unarmed western-backed Free Syrian Police force has ended up in the hands of jihadis linked to extremist groups.

The report, Jihadis You Pay For, will claim that Foreign Office money paid to the FSP reached people with links to the extremist group al-Nusra Front.

The allegations have been described as “entirely inaccurate and misleading” by Adam Smith International (ASI), which manages the British-funded Access to Justice and Community Security (Ajacs) scheme that supports the FSP in rebel-held areas of Syria. An internal review found that of $20m in funds for the FSP, only $1,800 unwittingly fell into the hands of FSP officers with links to extremist groups, and the cash was not British taxpayers’ money but from other state donors.

ASI has called on the BBC to amend the title of its programme, which has been described on the corporation’s website as an examination of “how some of the cash has ended up in the hands of extremists and how an organisation we are funding supports a brutal justice system”.

Andrew Mitchell MP, the former international development secretary, said it was inevitable the FSP would come into contact with extremist groups and that complexity should not deter the UK from involvement.

Mitchell warned against the BBC jumping on an “anti-aid bandwagon” and not taking into account the risks and difficulties faced in trying to offer communities policing outside of the control of the Assad regime.

“This is an extremely important project devised with the aim of strengthening the FSP in dangerous areas where jihadi groups are in operation,” Mitchell said. “That is the whole point. The people involved in the project are extremely brave and should be praised, not pilloried. The BBC have been told that there is no evidence of British taxpayers’ money going to jihadi groups.

“I hope they reflect on the information provided to them ahead of broadcast and don’t fall into the trap of criticising something without understanding all the facts and complexities of the area and the work being done. This work is too important to fall victim to an anti-aid narrative.”

Panorama is expected to claim that ASI failed to respond quickly enough when links were discovered between two FSP stations and courts run by al-Nusra. It is claimed that two officers were present at a stoning in 2014. ASI says the incident cited by Panorama occurred five weeks after it started working on the scheme in October 2014, and that the two men at the stoning were not formal officers and had not received any cash through the scheme.

Support for the police stations in the area was suspended the following February because of the heavy presence of extremist groups, ASI said.

Among Panorama’s other claims are that stipends paid to officers have continued even when they have died, the money going to the men’s families or relatives who replaced the officers. ASI says that a review last year found that this had happened in 14 cases.

General Adeeb al-Shallaf, founder of the FSP, a force of 3,300 mostly unarmed officers in the rebel-held areas of Aleppo, Idlib and Daraa provinces, accused Panorama of irresponsible journalism.

Al-Shallaf, who once held a senior position within Assad’s Syrian government police force before defecting when his superiors ordered him to shoot at demonstrators during the popular uprisings in the country, said: “We, the Free Syrian Police, are present on the ground despite all the challenges, be it the armed groups and the daily shelling – in the last shelling they hit our police centre in Al-Atarib and killed 13 police officers, in addition to civilians.”

The Foreign Office, which funds the Ajacs with five other governments, said the scheme was important for Britain’s national security but that it had suspended the funding while investigations continued. “These schemes, also supported by international partners, are intended to make communities in Syria safer by providing basic civilian policing services,” it said.

“We believe that such work in Syria is important to protect our national security interest but, of course, we reach this judgment carefully, given that in such a challenging environment no activity is without risk.”

The BBC said it “is confident in its journalism and the investigation will be broadcast in full”.