Found 2M for £1.81; ordered

At that price - not too much to waste!

You could always find someone with a suitable crimp tool and make that into a couple of shorter lengths too.

On the same subject of the RJ11 cables I have recently gone to FTTC and BT installed the Modem within half a metre of the master socket but used a 5m flat cable so I was looking for a shorter twisted pair cable to cut down on the risk of interference.
The BT cable is pin for pin. ie pin 3 to pin 3. All the replacements I have seen are crossover ie pin 2 to pin 3 does this matter?

As long as the pairs are respected, it's not a problem for xDSL. The pairs run from inside out, so 3&4 are paired, 2&5 and 1&6. In general, only the 3&4 are used for an xDSL modem.

Great, Thanks for the info. Its not mentioned anywhere and I didn't want to introduce an issue.

In reply to a post by TheEulerID:

As long as the pairs are respected, it's not a problem for xDSL. The pairs run from inside out, so 3&4 are paired, 2&5 and 1&6. In general, only the 3&4 are used for an xDSL modem.

Some modems are designed to work on either pair and will check both for the xDSL signal. They can be set to Inner/Outer/Auto select. 2wire are one manufacturer with it on their devices.

If there are two xDSL services to a premises and they are delivered on a single drop then an RJ11 splitter can be installed and two modems connected with Inner selected on one and Outer on the other.