Hoaxers force Number 10 to change its number

As text messages go, it made better sense than most: "Hi mate, phone me ASAP, crap signal in this pub. If I don't answer, ask for Tony who runs the place."

As text messages go, it made better sense than most: "Hi mate, phone me ASAP, crap signal in this pub. If I don't answer, ask for Tony who runs the place."

Thousands who received the hoax message last week rang the number, and were answered by No 10 Downing Street, to the surprise of both sides. Officials yesterday said they had been forced to set up a private line for ministers, civil servants and others with a genuine reason for calling the Prime Minister's official residence. Those ringing the main switchboard heard a recorded message telling them to hang up unless they were calling on government business. And a hunt was on for the hoaxer.

The mischievous text message was almost certainly relayed from a foreign phone network to British cellphones, in text "spamming", sending advertising or other messages to numbers almost at random in the hope of a response.

But it was also in the longstanding tradition of the pranks in which people are asked to call a number and ask for Mr C. Lyon or Mr LE Phant. (The number is a zoo.)

Last week at Downing Street the spoof calls amounted to four out of five of all calls, and there are thousands of genuine calls every day.

A No 10 spokeswoman said: "The increase in calls has put enormous pressure on our small team of switchboard operators who have a very difficult and responsible job to do. We had to take action to protect them."

In one sense the prank was ironic: the Labour Party used a similar system to send thousands of text messages to young voters at the last election, urging them to vote.

A similar prank was pulled a couple of months ago involving Buckingham Palace's number, in which people were urged to speak to Liz. That too overwhelmed their switchboard.

If the prankster is caught, he or she – and the company which helped them – could face charges under the Data Protection Act, and causing a nuisance.

But with the total volume of text messages sent in the UK hitting a new high of 1.4 billion per month, the chances of such "flash crowds" being created by pranks is growing.

At the same time, another risk is also raising its head, or perhaps hand. Yesterday the British Chiropractic Association warned that excessive text messaging can lead to repetitive strain injury (RSI).