Blocked underground U Bend

[dttrinity]

It seems that the U Bend in the trap below a rainwater downpipe is blocked and I can't get it cleared. I'm a real novice! Any help would be appreciated
😕

 

[wrecked_24_7]

get yourself a unblocking coil/waste coil etc. forget the correct term, its just a long piece of bendty metal that you can fit down most tight corners etc, as a drain rod isnt very flexible and probably wouldnt bend enough, you can find them at screwfix etc, for about £15 if i rememebr rightly

 

[dttrinity]

Thanks for that advice. I'll try and locate the tool you suggest.