On the 28th March 1845, John Tawell was hung for killing his mistress. This was not an unusual conviction, but the way that Mr Tawell was caught certainly was. He had been tracked down by the use of an electric telegraph!

The Electric Magnetic Telegraph first operated between Paddington and Hanwell in 1839 and in 1843 was extended to Slough.

So what happened? On 1st January 1845 John Tawell travelled from London to Slough to visit his mistress Sarah Hart on Salt Hill. He was carrying cyanide of potassium, a deadly poison, which he gave to Sarah in a glass of stout. Sarah's screams after drinking the poison alerted the neighbours and Tawell was seen leaving the cottage and hurrying back to Slough Railway Station.

He returned to London, spent a relaxing evening in local coffeehouses before going to his lodgings for the night. The following morning the police arrested him there.

How was he caught so quickly? News of the murder, complete with Tawell's description, reached the police in Paddington by telegraph only minutes after it had taken place. A policeman in plain clothes met Tawell's train at Paddington and followed the suspect to his lodgings and then waited for a representative from Slough to make the arrest.

This sensational capture raised the profile of the telegraph, but unfortunately it had to be removed in 1849, as it was not making enough money. The service was reinstated as part of a general installation across the railways in 1851.