There’s a saying that something is as easy as pie…but, in fact, fathoming out what is and isn’t a pie can be confusing.

So, with British Pie Week taking place until Sunday, let’s see what lies beneath the crust.

The name comes from magpie, a bird noted for its ability to hoard various random items, and reflects the fact that early pies had bits of everything thrown in.

The mixture of fruits and spices contained in the first mince pies brought back by Knights returning from the Crusades was one tasty example that has survived for 900 years. Thankfully the meat pies containing a mixture of crows, eels, cheese and frogs that also fed ye olde England have not.

But what, exactly, is a pie? One survey has Britain’s most popular pie as the Cottage Pie – basically minced beef with potato topping. Followed by Shepherds Pie where beef is replaced with lamb. But these can’t be proper pies – where‘s the pastry?

The Oxford English Dictionary is clear, a pie is a “baked dish with a top and base of pastry and a filling of fruit or meat and vegetables”. To suggest otherwise is just pie in the sky – a phrase meaning an unattainable goal first coined in a song by Joe Hill in 1911. It was a protest song about the conditions endured by workers, how they could afford little to eat but were promised “Pie in sky” when they died.

Recipes for meat pies date back to Roman times but it was in Britain of the Middle Ages that pies became popular with the masses. Ovens were a luxury in those days, expensive to build and requiring a lot of fuel to keep them going but pies could be cooked over an open fire so were easier to cook. The cheapest pies of all contained offal – heart, liver and entrails of an animal – also known as the umbles and so the phrase developed to eat humble pie.

At this time flour was highly prized – so re-useable earthenware pots were developed. These allowed the meat and vegetables to be cooked inside with just a pastry top to keep in the flavour – the origin of the pot pie and start of the debate as to whether a pie had to be encased in pastry all round.

How about cream pies?  No, they don’t count. Basically, a stage prop first appearing in 1909 in the black and white slapstick film Mr Flip, when actor Ben Turpin became the first person to receive an on screen pie in the face.

Fruit pies have been around for longer though, first appearing 500 years ago when cherry pie was served to Queen Elizabeth I. It was at that point that Britain’s taste in pies began to change depending on where you lived with the South going sweet and the North savoury.

Today steak and ale is the nation’s most popular proper pie overall but a survey by Hungryhouse, revealed stark regional variations. Londoners voted banoffee pie their favourite, Bristol went for apple pie, Birmingham favoured chicken and mushroom, Newcastle went for steak and potato and Glasgow the classic pork pie.

So, whilst tastes may vary, as a nation we are agreed, for a wholesome food that hits the spot just reach for the pies.