The UK government is to end funding to a scheme to support the Syrian opposition, deeming the programmes now too risky to operate as the final rebel-held areas face imminent attack from Bashar al-Assad’s forces.

Funding to support the operations of the Free Syria police force is set to come to an end in September, with government sources conceding the Access to Justice and Community Service (Ajacs) programme had become too difficult to deliver.

While humanitarian support will continue, the ending of this governance programme is highly symbolic, suggesting Britain has accepted that the Syrian opposition, which it has backed since the early days of the civil war in 2012 to 2013, is facing imminent defeat from a combination of Syrian regime forces and Russian airstrikes.

The government said the scheme had been kept under review because of the high risk, difficult conflict environment to ensure the benefits justified the risks, acknowledging the scheme had become too difficult to deliver as the balance between potential gain and risk shifted.

It said over recent months that the situation on the ground in those regions had become more difficult.

Instead, the focus in northern Syria is now on basic lifesaving needs, providing medicines and medical equipment and water and sanitation support.

The UK’s aid spend in 2017-18 was £152m, of which more than a third was delivered to Idlib, one of the last rebel-held areas on the Turkish border, reaching around 600,000 people.

Last week, Foreign Office minister Alistair Burt announced an additional £10m spend for emergency assistance and medical support for people who had fled to Idlib from other former rebel-held areas such as east Aleppo.

The Foreign Office and the Department for International Development (DfID) have denied the decision is related to a BBC Panorama investigation broadcast in December.

The programme claimed that the police force, which last year numbered around 3,300 mostly unarmed officers in the rebel-held areas of Aleppo, Idlib and Daraa provinces, had been under the sway of jihadist forces.

Following the programme in December, the Foreign Office suspended access to the Ajacs scheme, which has been running since late 2014, following the concerns raised about its management by the British contractor, Adam Smith International.

Britain was one of six countries supporting the community-led police force set up after the Syrian uprising in 2011.

The Panorama programme, Jihadis You Pay For, claimed police officers in Idlib province had to be approved by Jabhat al-Nusra and that police officers in Aleppo province were forced to hand over cash to Nour al-Din al-Zinki, another extremist group.

A DfID source stressed the decision to end the funding was not based on the programme’s findings and said the department continued to reject claims made in the documentary.

A UK government spokesperson said: “The UK is supporting thousands of vulnerable Syrians living in the north of the country by helping children to stay in school and securing jobs. This is in addition to providing lifesaving emergency aid for millions of vulnerable people.

“As the situation on the ground in some regions has become increasingly difficult, we have reduced support for some of our non-humanitarian programming, but continue to deliver vital support to help those most in need and to improve security and stability in the country.”

On Friday, the US state department announced it was cutting $230m (£180m) from its budget to stabilise areas of Syria captured from Isis, saying it had been compensated by $300m in extra contributions from Saudi Arabia, the United Arab Emirates and other US allies.