Forward primer: A-L-X-S1 Reverse primer: A-L-Y-S2 Wherein A represents a moiety which allows attachment to the solid support, L is an optional linker or spacer moiety, X and Y are optional cleavage sites as described above to allow subsequent removal of one or other of the strands from the surface and S1 and S2 are polynucleotide sequences which permit amplification of a template nucleic acid mole