what's wrong?

Thanks to all who answered, a new battery sorted it. Cheers.

Grizwold
March 2016

The battery has insufficient energy

Get a new one
December 2015

Check the big, heavy connection from battery to solenoid and from solenoid to motor.

Also check the earth cable from the engine block to the chassis and the heavy cable from the battery to the chassis. Check all connections in all heavy cables

If you can feel any warmth in any connection immediately after trying the starter, that connection is suspect and should be re-made.

XX
December 2015

The battery is not OK - it has Voltage but not enough energy to turn the engine over.

A Novice...
December 2015

if connections and battery are ok,renew starter

cdc
December 2015

The clicking may well be the starter solenoid actuating to switch power to the starter motor.

The starter motor might be bad
A power connection to the starter motor might be bad
The battery might be low on power

When the battery becomes flat on my little Escort the clicking symptom is what happens.

The voltage might appear to be OK but if the starter tries to draw the high current it needs the voltage will drop to be very low indeed - the starter solenoid drops out because of the low voltage - the starter stops drawing current - the voltages goes back to a higher value and it all happens again - click-click-click.

I suspect a battery on the way out. How old is it?

I am not a motor engineer - this is just a guess.

Good Luck...
December 2015