HI Giriesh,
as Jayanti as already suggested check Calculations within the Function GBNIC within your log for the current pay period, Check NI calculation summary and see if you your current NIable pay for TP has been adjusted by NI able pay form retro period (-£10,000.00). The amount is huge and it might happen that for this pay period employee might not have enough NIable pay to be adjusted from, could you please put screen shot here for your GBNIC calculations summary.
KR
Sid