A former police chief famed for forgiving the terrorist who murdered his son both entertained and enlightened when he spoke about his career in Letchworth on Sunday.

Robin Oake – whose son Stephen Oake, an anti-terror detective, was stabbed to death in 2003 – among other things recounted helping to deliver a baby on a roadside using a copy of the Daily Telegraph.

“I thought she might have named the baby after me,” he said. “But oh no. It was a girl.”

Robin drove down from his home near Shrewsbury to speak at the Christchurch Baldock service at Letchworth Free Church hall, watched by about 100 people.

On his first day in police training, he recalled, an instructor said: “You’ll meet the unexpected, you’ll never get rich – and keep your sense of humour.”

Robin described his days as a beat copper in London, his time as a counter-terrorism officer in Northern Ireland, his years serving in Manchester, and finally his period as the Isle of Man’s chief constable.

“It’s not all crime,” he said. “It’s helping people in distress.”

In London in 1957, he recounted, he chased down and arrested a thief who had snatched £40 – only to find the man had been in the Olympics the previous year as a walker.

Another time, Robin helped save the life of an American soldier who caught fire after a crash in Abbey Road. Later, when he was stationed in Soho, it emerged the manager of the Scotland Yard restaurant was also running a strip club.

Pointing to marks still visible on his face, Robin told how he had tried to stop a fight, only to be sent flying head-first down some stairs and into a Chinese gambling den – ‘which we’d been looking for for months’.

Moving on to Northern Ireland and Manchester, Robin showed how officers had flicked through books backwards as a precaution against IRA bombs – and told how Charlie Moore, one of the leaders of the 1981 Moss Side riots, had come to his station to ask forgiveness after becoming a Christian.

Later, amid clashes in India between Hindus and Sikhs, Robin helped to bring the two communities in Manchester together and prevent similar violence there.

Finally coming to the topic of his son Stephen’s murder, Robin told how his son had been killed by a member of a terror cell that had plotted to put ricin poison in London’s water supply.

“It still hurts,” he said. “You can imagine the trauma that was for all the family.”

After reading from Paul’s epistle to the Romans, Paul concluded with the verse from John’s gospel that appears on his son’s memorial: “Greater love has no one than this, that he lay down his life for his friends.”

Robin gave a free signed copy of his book The Power of Powerlessness to everyone who attended.

To find out more about Christchurch Baldock and its events, see christchurchbaldock.org.uk.