The blocking service was designed to help people who received large numbers of tele-marketing calls.

However, a survey by Which? found that 85% of people are still being plagued by unwanted phone calls, with one in 10 of them receiving, on average, a whopping 50 or more unsolicited calls each month.

Which? is calling for tougher Government action to deal with the scale of this problem.

Which? executive director, Richard Lloyd, said: “Consumers are sick and tired of being bombarded with nuisance calls and texts. The current system is failing the public and given the scale of this problem, it’s time for the Government to step in.”

The survey found that people registered with the TPS still received, on average, 10 unsolicited calls in the last month – compared to five calls, on average, received by those not signed up.

More than half of those registered on the TPS said they felt they were receiving fewer calls than they did prior to signing up.

In March this year, Which? asked the Information Commissioner’s Office (ICO), the Ministry of Justice, Ofcom and the Office of Fair Trading (OFT) to form a joint taskforce within 12 weeks to stop unwanted calls and texts.

The TPS’s limited remit means it can’t punish companies that break the law or even compel them to respond to its letters. Instead, enforcement action is undertaken by the ICO.

The regulators have confirmed to Which? that they need more powers to properly tackle the problem of nuisance calls and texts.

Lloyd added: “We urgently need to see a new approach, new laws and new technology to tackle this scourge on people’s lives. People must be put back in control of their personal data.”