Britain's most senior immigration judge has criticised taxpayer-funded lawyers of being 'cavalier and unprofessional' in helping a child sex-grooming gang avoid deportation from the UK.

Mr Justice Bernard McCloskey launched the damning attack in response to an appeal made by the Rochdale sex gang against the decision of then-Home Secretary Theresa May in 2012 to strip them of their British citizenship and deport them.

Paedophile Shabir Ahmed, 63 - the ringleader of the Rochdale gang - wrote to the European Court of Human Rights (ECHR) to appeal against his impending deportation from the UK.

Three other men convicted in the case, Abdul Aziz, Adil Khan and Abdul Rauf, are also appealing against being stripped of their citizenship.

Paedophile Shabir Ahmed, 63 - the ringleader of the Rochdale gang (left) and Taxi driver Abdul Aziz, 41, (right) are both appealing the decision to strip them of their citizenship

Mr Justice Bernard McCloskey launched the damning attack about the gang's solicitors, Nottingham-based firm Burton and Burton, in an immigration tribunal

Justice McCloskey made the comments about the gang's solicitors, Nottingham-based firm Burton and Burton, in an immigration tribunal.

Ahmed was convicted in 2012 of being the ringleader of a group of Asian men who preyed on girls as young as 13 in Rochdale, plying them with drink and drugs before they were 'passed around' for sex.

His case sparked fears about how foreign criminals are trying to exploit human rights laws to remain in the country.

Ahmed was given a 19-year sentence at Liverpool Crown Court in May 2012 for a string of child sex offences, including rape.

He was also jailed for 22 years, to run concurrently, in July 2012 for 30 rapes against another victim.

Burton and Burton are funded by the taxpayer via legal aid, with their fees reported to be £50 to £70 an hour, according to the Telegraph.

Three other men convicted in the case, including Abdul Rauf (left) and Adil Khan (right), are also appealing against being stripped of their citizenship

Justice McCloskey said: 'The conduct of these appeals has been cavalier and unprofessional. The rule of law has been weakened in consequence.'

The judge also threatened the legal team with disciplinary action, warning them their actions could be in contempt of court.

He added: 'Scarce judicial and administrative resources have been wasted in dealing with repeated unmeritorious requests by the Appellants’ solicitors for an adjournment.'

Kabeer Hassan, 25, was sentenced to nine years for rape and conspiracy (left) while taxi driver Abdul Huk was found guilty of sexual activity with a child and was jailed for four years

Taxi driver Rauf, 47, a father-of-five, was released on licence in 2015 after serving half of a six-year sentence for trafficking a girl, aged 15, in the UK for sex, and for having sex with the youngster himself.

Rauf, who also acted as a religious studies teacher at a mosque in Rochdale, burst into tears, and through his Urdu interpreter asked the immigration tribunal for 'mercy' and that he 'wanted a second chance'.

Ahmed, known as Daddy, previously took his case to the European Court of Human Rights (ECHR) claiming that his all-white jury was biased – a breach of Article 6 of the European Convention on Human Rights, guaranteeing a fair trial.

But judges in Strasbourg unanimously threw out his case, insisitng that there was 'simply no proof' jurors acted improperly.

They dismissed the claim as 'manifestly ill-founded'.