Leave them on unless you want them to flop all over the place. They use these tendrils to climb up twiggy structures, wire or string.

Leave them on.

leave them on, but cut the flowers regularly and they flower more...

Thank you all for your advice regarding my sweetpeas - BUT .. I leave the tendrils on until they have reached the top but after that, they tend to cling to eachother and get very tangled. Someone said "Take them off".

I do half and half . I leave the ones that cling to supports and nip off the others so that they don,t cling and distort growth

Thanks Helen60garden that answers my question