Hole in chassis...

Today I noticed that I have a hole in my 2001 D2 chassis on the section which supports the fuel tank.

Here's a pic:
http://farm9.staticflickr.com/8517/8387888198_57b52f42db_h.jpg

The pic isn't the best but the fuel tank is at the top.

Is this an MOT fail and how much am I looking at to get it repaired? The car was only MOT'd 2500 miles ago before I bought it so I'm not sure why it wasn't spotted.

ther well known for going like swiss cheese on rear chassis a dew threads on it

Do you know if it would fail an MOT for it and how easy & costly would it be to repair?

from the posts on here it i more than likely to be bad from axle back have you tried wire brushing to see how bad it is. If not to bad patch if rot is rife it could be about 1500 for rear quarter have a search great thread on it.

just looked at pic a plate should do that as long as rest of chassis is sound.

I'd stop it before it goes any further. Get a small hammer and punch and see hoe far it goes. Drop the tank and get a plate on it.

Also, looking at the pic it looks to me like it has been welded on the side before. Or am I incorrect?

Just had a plate welded on mine cost £35. but yours needs fuel tank removing.