knifeman described as “one of the most dangerous men in Britain” after attempting to murder two police officers has been told by top judges that his 25-year minimum jail term was not a day too long.

John Onyenaychi, 31, cut Pc Paul Madden’s throat and slashed at PCSO Piotr Dolata in Ealing when he was detained after revenue inspectors removed him from a bus in December 2010.

That attack was the culmination of a five-day spree of knife crime and, at London’s Old Bailey in October Onyenaychi was jailed for life.

He had been convicted of two counts of attempted murder, one of robbery, one of wounding with intent to cause grievous bodily harm, plus an attempted wounding.

A 25-year minimum term was set on the life sentence.

A senior police officer had said after Onyenaychi was convicted that he was “one of the most dangerous men in Britain”.

Onyenaychi, of Wise Road, Stratford, asked Lord Justice Hooper, Mr Justice Maddison and Judge James Goss QC, sitting at London’s Criminal Appeal Court, to reduce that minimum term.

The court heard Onyenaychi cut Pc Madden’s throat as horrified bystanders watched and then lashed out with his knife at other officers who tried to restrain him, wounding Mr Dolata in the head.

He had been removed from a bus in Ealing Broadway and police had been called to the scene when it was realised he was the man wanted for a knife-point robbery of a man in his home and a stabbing in a taxi office, both committed just days before.

A retired doctor, who was by chance passing by, saved Pc Madden from bleeding to death due to injuries to his jugular vein, and the judge passing sentence told the knifeman that there was “a hair’s breadth” in this case between murder and attempted murder.

Lawyers for Onyenaychi argued that the judge had not sentenced him for attempted murder, but as if he had carried out the full offence.

But Mr Justice Maddison threw the case out, saying: “We don’t accept that the judge failed to allow sufficiently for this distinction.

“The starting point, had this been a murder case, would have been 30 years.

“For the murder of a police officer with a knife for a man with his previous record, we would expect a minimum period well in excess of 30 years.

“We accept that this was a very substantial sentence, but it is not properly arguable that it was a manifestly excessive sentence.

“This application must be refused,” the judge concluded.