David - I think this could be Alan Wallwork.
Vincent - Thank you but not AW. Mark is an interconnecting LM or LH (but not Louis Hudson). A Scandinavian origin has been suggested.
arthur lewthwaite - having worked for in the sixties iwould say this is not an alan pot .i9ddented decoration to sparce.black and white glazses to bright,and more ochre colouring would be present,ialso think black and white would have been done with slips rather than glaze to give the subtle stoneware effect alan liked to achive.