On April 4, 2012, the existing analogue television signal received by homes across Wandsworth will be switched off and replaced with a new, stronger digital TV signal.

In order to continue watching television, residents will need to convert their TVs to digital before the switchover date.

Wandsworth Council is now warning about the potential threat posed by doorstep con-artists, who may attempt to pose as switchover contractors in a bid to gain access to homes or con vulnerable people out of money.

Anyone over 75 years old or registered disabled will be sent an official information pack explaining the changeover process. No one will call on homes unexpectedly without an appointment.

The Digital UK information pack will say whether a household is entitled to a free changeover and explain how an appointment can be arranged.

A password system can be put in place if the home owner wishes and they can request a member of their family, neighbour or friend to be present whilst a registered fitter is in the home.

The council's community safety spokesman, Councillor Jonathan Cook, said: "Thankfully there have not yet been any reports of digital TV changeover scams or related distraction burglaries - and we want it to stay that way.

"As well as asking older, more vulnerable residents to be wary of bogus doorstep callers, I hope their relatives, friends and neighbours will also be alert to the threat these fraudsters pose.

"We want to make sure that none of our residents fall prey to any criminals who may use the switchover as an opportunity to fleece people out of money."

If anyone suspects they have been ripped off, paid a deposit to a trader they're now worried about, or suspect there's a rogue trader working door-to-door in their area, they should call the Consumer Direct helpline on 08454 04 05 06.

Alternatively, any resident wanting face-to-face help can visit Wandsworth Citizens Advice Bureaux branches in Balham High Road, Bolingbroke Grove or Roehampton Lane . Age UK also offers advice about the changeover at http://www.ageuk.org.uk/

Many people will be receiving messages on their televisions now from Digital UK saying that the switchover is taking place - but channels will not be lost until after April 4.

For more information about the digital changeover call the UK Digital London region helpline on 0800 408 59 18 or visit http://www.digitaluk.co.uk/

Digital UK 's tips for avoiding scams:

Remember that no one from Digital UK or Switchover Helpscheme will call unexpectedly without an appointment.

Demand identification from uninvited callers - and call the company to check they are who they say they are.

Don't agree to any work on the spot. Take time to think about what work (if any) you want done.

Only buy goods and services you need for switchover from reputable retailers and traders that carry the digital tick logo

If an offer seems too good to be true - in a leaflet, advert, by phone, e-mail or personal approach - it probably is. Be wary and read the details of the deal carefully.

Calls to the Consumer Direct helpline cost 4p per minute from a BT landline; from mobile and non BT lines call costs may vary.