Cryptic messages concealed on the internet are being used to lure talented codebreakers to a career with British intelligence.

GCHQ, which eavesdrops on global communications for the government, has placed a series of codes on its website and invited visitors to crack them.

The five-part puzzle unravels to form a message to potential job applicants, who may find their chances of employment greatly enhanced by cracking the code.

The unusual recruitment drive is reminiscent of the World War II effort to crack the Enigma code, used to direct German U-boats to their targets.

Station X

Then, keen crossword solvers, mathematicians, academics and chess masters were recruited to work at Bletchely Park - known as Station X - near Milton Keynes.

Their skills in cryptic analysis proved crucial in developing early computer technology, which succeeded on cracking the code.

The hidden code was posted on GCHQ's website before Christmas and the first person cracked it successfully within 48 hours. Eleven others have managed it since.

A GCHQ spokeswoman said the code, backed by a national newspaper campaign to recruit technologists and linguists, was aimed at catching the imagination of would-be applicants to fill up to 100 new vacancies.

"It is certainly a new way of contacting potential employees and it gives us an indication of the kind of skills we are looking for," she said.

"We hope people will be interested and challenged to have a go to see what they can find."

But those who do manage to crack the code are warned not to hand in their notice straight away.

All GCHQ applicants undergo a two-month vetting procedure in which their professional and private lives are placed under scrutiny - a process that may deter some of the internet's more "creative" hackers.