The male teenagers were barred permanently from the Thomas Deacon Academy following a "three strikes and you're out" rule.

The news is set to add further fuel to the fire to claims that academies are employing a back-door selection policy, which sees weaker pupils being weeded out and dumped on other schools, which have to take them, in a bid to boost exam results.

Statistics released under the Freedom of Information Act in August showed that 8.7 pupils per thousand were excluded from a sample of 14 academies during the past school year.

By comparison, 3.2 pupils per thousand were excluded from secondary schools in their neighbouring areas, according to an analysis published in Regeneration and Renewal magazine.

But today, principal of the £50 million school, on Queen's Gardens, Peterborough, Dr Alan McMurdo, said the statistics showed they were actually bucking the national trend.

He said: "The going rate nationally for academies that have converged two schools together is two per cent.

"We are delighted that our pupils are nothing like that in terms of exclusions.

"No one usually goes straight out, it's a three strikes and you're out rule. However, if it's really serious, they will go straight away.

"There was some violence in one of the cases, and repeated disruption and an inability to follow instructions in the other.

"We have got to ensure the kids are kept safe."

He added: "We were bracing ourselves for two per cent, which is 40 pupils, in our first year.

"Approaching half term, we are on 0.1 per cent."

Exclusion rates at some of the Government's academies are four times as high as the average at neighbouring schools.

However, Government ministers claim academies are placing a bigger emphasis on getting the basics right and improving behaviour.

Academies inherit some disruptive pupils and need to establish good behaviour in order to raise standards. Dr McMurdo said that as the new ethos is enforced in an academy's early days, the number of exclusions may rise, but it typically drops as behaviour improves.

He also said the link between excluded pupils and poor academic ability was tenuous.

He said: "The excluded pupils are not always academically less able. Exclusion is never based on academic ability, and often you find these youngsters are quite bright."

Meanwhile, across the rest of Peterborough, there have been no permanent exclusions and 34 periods of fixed term exclusion in secondary schools.

This refers to the number of times pupils have been excluded since the beginning of term and may include those who may have been excluded more than once.