What is this spring from?

[VintageBike]

Hi,
can anyone help me?  I've been clearing out my garage and I have come across a few bits that I cannot work out...  I've asked all of my contacts and have drawn only a blank, so I thought I'd turn to the guys who really know...

It's a spring with a flat profile, about 9" in length with a square base as you can see in the pictures.

Any ideas?

Thanks in anticipation.....

Nigel
www.vintagebike.co.uk

[VintageBike]

another pic

[VintageBike]

For those interested, this turned out to be the fork spring from a 1929 Francis Barnett "Built Like a Bridge".

Got there in the end...

Cheers

Nigel