Britain can only deport foreign terrorists hiding behind human rights laws to two countries at a time because the process is too expensive, a long-awaited review has revealed. Dangerous jihadists who pose a threat to national security cannot be sent back to a long list of countries including Libya, Egypt, Syria, Pakistan, Sudan, Yemen and Russia even if a guarantee of fair treatment is obtained, according to the report ordered by Theresa May. Where assurances can be sought – as they were in the case of Abu Qatada – the process is so complicated and costly the Home Office has admitted that it can only manage negotiations with two nations at a time. Professor Clive Walker, an international law expert who co-authored the report with David Anderson QC, the then independent reviewer of terrorism legislation, estimates that the number of foreign jihadists who could avoid deportation “probably exceeded 40”. His analysis goes on to warn that with increasing travel to Syria and Iraq and restrictions on leave to remain conditions that number could “now markedly increase”. The review of Deportation with Assurances (DWA) – which was ordered by Mrs May when she was Home Secretary in 2013 but only published quietly last month – concludes that it remains an important tool. The scheme in theory allows the UK to expel suspects with guarantees they will not be mistreated or tortured in their home country, but in the last 13 years it has only led to the deportation of 11 people – nine to Algeria and two to Jordan. In contrast, France has deported around 120 suspected terrorists. The failures of the initiative which she pushed hard for have the potential to cause some embarrassment for Mrs May. The most high profile case was her battle with Abu Qatada which, after eight years and a legal bill of £1.7million, she finally won in 2013 when he boarded a plane to Jordan. Mr Anderson QC, who has revealed that during what he described as the “cartoon battle” the al-Qaeda linked cleric labelled his opponent “Crazy May”, said in his review that now cases have been taken all the way to the Supreme Court future hearings are likely to be much shorter. “We are very grateful to David Anderson QC for his report and we are pleased with his recognition that the UK has taken the lead in developing rights-compliant procedures.”Keeping the public safe is our primary duty and DWA is one of a range of powers available to disrupt terrorists.”They denied that funds were an issue when dealing with DWA cases. The Home Office said that it had previously managed negotiations with at least four countries simultaneously. Abu Qatda called Theresa May ‘Crazy May’ during their legal battle over his deportationCredit:Getty Images But the hurdles remain almost insurmountable because of the increasing political instability around the world and the fact that the Government has expressed its intention to remain signatory to the European Convention on Human Rights. Furthermore, Mr Anderson QC was told in 2014 that “the Home Office only had the resources to contemplate the use of DWA in a maximum of two countries at any one time.”Alongside the legal costs associated with deportation and the difficulty of negotiating a memorandum of understanding, the deported person must be monitored to ensure that the conditions are not breached which can “consume huge resources in terms of money and time”.Because of condemnation of DWA from NGOs and international lawyers, charities often refuse to be associated with it, forcing the Government to fund the setting up of organisations that can monitor the deportees welfare. In Jordan, this was the Adaleh Centre which is said to have “substantially benefited from grants from Her Majesty’s Government”. Though it is unclear how much this cost, Mr Anderson noted in his report that when he visited in 2014 it “had 14 full-time and three part-time employees, with 70% of its work being for the Jordanian Government but 50% of its funding being provided (at the time) by the UK Government. “ Only six countries have entered into arrangement for DWA from the UK – Libya, Ethiopia, Algeria, Lebanon, Morocco and Jordan – of which the first three have since been ruled out because of political instability and risk of mistreatment. Professor Walker’s analysis notes that in “rare cases” the ECtHR has said that assurances will not be enough. He advises that these cases could be defined as the “Countries of Concern” designated by the Foreign and Commonwealth Office each year because of concern over their human rights. After the DWA report was published by the Home Office, almost six months after they received it, Mr Anderson QC concluded on his blog: “The obstacles are now formidable. It remains to be seen whether the Government retains the stomach for the fight.”Professor Walker told the Telegraph: “It is legitimate but practically very difficult. Because of the failure of the Arab Spring democracy and human rights movements in many of the countries concerned, Egypt, Algeria, the prospects don’t look very bright that it is going to be taken forward on any industrial scale so we have to think about the long time management of people here.” A Home Office spokesman said: “DWA remains a valuable policy which allows us to remove those who threaten to do us harm while meeting international human rights obligations. Show more Mr Anderson backs Professor Walker’s conclusion that: “DWA can play a significant role in counter-terrorism, especially in prominent and otherwise intractable cases which are worth the cost and effort, but it will be delivered effectively and legitimately in international law only if laborious care is taken.” Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.