This coin comes in several variants, each with minute differences.
A British 1771 copper Farthing (KG III)(Reverse "A" - Britannias leaf to right), circulated but still in good condition, might fetch anything from £20 to £250 GBP.
A British 1771 copper Farthing (KG III)(Reverse "B" - Britannias leaf points to "N" in BRITAN), circulated but still in good condition, might fetch anything from £20 to £250 GBP.
A British 1771 copper Farthing (KG III)(Reverse "C" - Britannias leaves point between "A" and "N" in BRITAN), circulated but still in good condition, might fetch anything from £20 to £250 GBP.
A British 1771 copper Farthing (KG III)(first "7" of date is a "1"), circulated but still in good condition, might fetch anything from £30 to £475 GBP.
A reputable coin dealer will be able to give a more accurate valuation.
NOTE - The reverse of these coins is upside down to the obverse. This is normal.
The last British Farthing was minted in 1956.
The last British Half-Farthing coin was issued in 1868.
The farthing was last produced in Great Britain in 1956.
All British 20th century Farthings were made from bronze. If you have a gold Farthing, it is because somebody has plated it. Modified coins have no collector value.
All British 20th century Farthings were made from bronze. If you have a gold Farthing, it is because somebody has plated it. Modified coins have no collector value.
There were no British Farthings minted from 1776 to 1798 inclusive.
There were no British Farthings minted from 1808 to 1820 inclusive.
Such a coin does not exist. The Royal Mint produced no Farthing coins in 1870 or 1871.
Such a coin does not exist. The last British Farthing was minted in 1956 and they were demonetised in 1960.
Such a coin does not exist. The Farthing was last issued in 1956 and withdrawn from circulation and demonetised in 1960.
Farthings were made from bronze. If you have a silver Farthing, somebody has plated it and it is subsequently of no value as a collectible.
Farthings were made from bronze. If your Farthing appears to be gold, somebody has probably gold plated it. Modified coins have no collector value.