The tradition of eating chocolate at Easter is tied to Lent. During the six weeks before Easter, known as Lent, Christians abstained from consuming animal products. This included all dairy and eggs.

Why do we eat chocolate eggs at Easter in the UK?

Early Easter Eggs

Eggs represent new life and rebirth, and it's thought that this ancient custom became a part of Easter celebrations. In the medieval period, eating eggs was forbidden during Lent (the 40 days before Easter) so on Easter Sunday, tucking into an egg was a real treat!

Why do we celebrate Easter with chocolate eggs and bunnies?

According to Discovery News, since ancient times, eggs and rabbits have been a symbol of fertility, while spring has been a symbol of rebirth. So even though rabbits don't lay eggs, the association of these symbols was almost natural. ... The Easter bunny and Easter eggs originated as pagan symbols of spring and rebirth.