Other contributors have said "Decimal currency replaces pounds shillings and pence?" is the same question as "When was the British decimal currency introduced?" If you believe that these are not asking the same thing and should be answered differently, click here
British decimal currency was scheduled for the 15th of February, 1971, but the 5 and 10 New Pence coins were issued much earlier in 1968 and circulated along with the similar sized 1 and 2 Shilling coins they were to replace.
Decimal currency was officially introduced in Britain on "Decimal Day" the 15th of February, 1971, with the Half New Penny, 1 New Penny and 2 New Pence coins being issued. The 5 and 10 New Pence...