Quite possibly the end of the hose has perished with age. Everything might look fine, but the structure of the hose may be failing.

It is more likely that the filler neck has rusted through somewhere if it only happens when you fill up with fuel. There are two pipes, the main one and a smaller one to allow air to escape the tank during filling.

The problem is and I have been under the car while it is being filled is with the rubber hose the first clip that connects the tank with the filler pipe..

It is coming out the end of the hose quite bad and as said earlier I have examined the hose and pipe and all seems ok...

Is there something like I said that can push the petrol back through the pipe at the same time filling tank like venting or pressure..of course when you have finish fueling there is no problem...

I am thinking that the connection of the pipe with a proper Jubilee clip not a cheap copy was not enough to secure the pipe tight enough because if you saw the OM Clips they are very strong and heavy duty and have a bolt in the middle of the clip that tightens 2 strong wire up at the same time..

It looked so simple to fix when first thought but it as turned out to be a bit of a nightmare...