The government was warned three years ago that stripping people of their citizenship may be an “ineffective and counter-productive weapon against terrorism”, it has emerged.

After making an order to strip Shamima Begum of her British nationality, Sajid Javid said he would not hesitate to use the power “if it is the only option left for me to protect everyone that lives in the UK”.

But official documents reveal a government-commissioned review warned in 2016 that removing extremists’ citizenship left them free to continue terrorist activities abroad, prevented monitoring and encouraged the “dangerous delusion that terrorism can be made into a foreign problem”.

Home Office statistics show the government has stripped more than 150 people of British citizenship for the “public good” since 2010.

The power was used only a handful of times a year, until deprivations rocketed from 14 people in 2016 to 104 in 2017.

Syria at war: Fleeing the caliphate Show all 14 1 /14 Syria at war: Fleeing the caliphate Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria Richard Hall/The Independent Syria at war: Fleeing the caliphate Zikia Ibrahim, 28, with her two-year-old son and 8-month-old daughter, after fleeing the Isis caliphate Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Men who fled the last Isis-held area of Syria line up to be questioned by American and Kurdish intelligence officials Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate A young girl pulls her belongings after arriving Richard Hall/The Independent Syria at war: Fleeing the caliphate An SDF fighter hands out bread to women and children after they arrive Richard Hall/The Independent Syria at war: Fleeing the caliphate Sita Ghazzar, 70, after fleeing from the last Isis-held territory in Syria Richard Hall/The Independent Syria at war: Fleeing the caliphate A family from Russia who recently fled the last Isis-held area of Syria Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria. Richard Hall Richard Hall/The Independent Syria at war: Fleeing the caliphate Richard Hall Richard Hall/The Independent

The Home Office declined to provide a reason for the dramatic increase, a breakdown of cases, information on the justifications used or what happened to the individuals targeted.

Mr Javid has been accused of using the power as an “easy way out” rather than repatriating alleged Isis fighters to face trial, with figures showing that only one in 10 jihadis returning from Syria has been successfully prosecuted.

Lord Anderson, the former independent reviewer of terrorism legislation, said a “scrutiny blackhole” made the impact of citizenship deprivations impossible to assess.

“There hasn’t been independent scrutiny of the exercise of this power, except in the occasional case that might end up in court,” he told The Independent.

“The independent review of counterterrorism law has served this country very well.

“It should in my view be extended to the use of citizenship deprivation powers, which is often used as a counterterrorism instrument.”

Lord Anderson was asked to review changes to the law that allowed the home secretary to strip naturalised British citizens of their nationality, even where they would be made stateless, in the belief they were eligible for the citizenship of another country.

His 2016 report warned that: “A citizenship deprivation power has been characterised as an ineffective and counter-productive weapon against terrorism.”

Shamima Begum's child could retain British citizenship, admits Sajid Javid

It quoted research by academics in Canada saying it amounted to “a policy of catch and release, setting up today’s convicts as tomorrow’s foreign fighters” and exporting them to places where they can do more damage because they cannot be monitored.

They warned that citizenship deprivations encouraged “the dangerous delusion that terrorism is (or can be made into) a foreign threat and problem”.

When asked whether it was easier to control terrorists in the UK or by preventing them from returning to the country last week, Metropolitan Police commissioner Cressida Dick said it was a “very hard question for anyone to answer”.

“It is very dependent on the context,” she added. “That decision is made by the home secretary and government.”

A 2017 inspection by the independent chief inspector of borders and immigration concluded: “The effectiveness of [citizenship removal] in protecting the UK from national security threats is hard to assess and is a question for the home secretary and security and intelligence agencies to answer.”

A report said the national security case for citizenship deprivations was normally made by intelligence agencies, with submissions cleared by senior managers and Home Office legal advisers before being sent to the home secretary.

Raffaello Pantucci, director of international security studies at the Royal United Services Institute (Rusi), said British extremists who fought for al-Qaeda and al-Shabaab had been targeted in the past.

“I don’t think it really deals with the problem, we just shunt it on to someone else,” he told The Independent.

Shamima Begum was stripped of her British citizenship after being interviewed by journalists in Syria (Reuters)

“You’re just absolving yourself of responsibility for an individual but you’re not dealing with the issue.”

Mr Pantucci said that terrorists prevented from entering the UK can still target “western interests” abroad, such as tourist sites.

“If we know enough about an individual to deprive them of citizenship, then presumably we know enough about them to track them quite closely,” he added.

None of the four fatal terror attacks launched in London and Manchester in 2017 was carried out by returnees from Iraq and Syria, although Manchester bomber Salman Abedi had fought in Libya.

A Home Office spokesperson said: “The home secretary’s priority is to keep Britain safe and he has a range of tools to do this. They include the power to deprive people who pose a serious threat of their British citizenship where it would not make them stateless.

“We have been open and transparent about the use of this power, publishing reports as recently as last summer, setting out the number of deprivations.