What year did the English mint change from copper coins and pennies?

The last copper coins minted by the Royal Mint were minted in 1860.

Since then, "copper" coins have been made from bronze which, depending on the year, has a copper content of anything between 92% and 98% copper.

More recently, in 1992, the Royal Mint changed from bronze 1 Penny and 2 Pence coins, to more cost effective copper plated steel coins.