Recomendations for extended rj11 modem cable

[#1]

I am looking to move my router setup about 5 metres away from the master socket and need a longer modem cable rj11 to rj11. Can anyone recommend a min spec cable to get to ensure that the move doesn't knacker my speed.
Any category of cable I should look for?
Any particular make?
Any good reseller?
Many thanks,
Podman

[#2]

Have not used them.... but these seem to have a 4.5 star rating from customers...
http://www.cables2u.co.uk/modem-telephone-adsl-c-27.html?gclid=CNm8xtDJ-7ECFaUmtAodEn4Arg
and they do.... 15mtr  10mtr  5mtr  3 mtr  in black or white.... and from about £8.50 down to about £1.50 depending on colour and length..

[#3]

Cheers,
managed to get a cable for 1/2 price from pcworld. It's 10 m and now i find I only needed less than 5 the majority is still wound up at the socket. The router now sits havf way along the wall with the other longer cables all tied up next to it.
Not sure how much damage a more longer than necessary cable can do.

podman