TOMORROW is the last day of Passover. For many Jews the end of Passover means one thing: they can finally have toast for breakfast.

Throughout Passover observant Jews eat only matzah — a sort of oversized cracker. Because these are made without yeast, they remain entirely flat and so are described as unleavened. The matzahs are supposed to symbolise the fact that when the Jews fled Egypt, they did not have time to let the bread rise properly and so took only unleavened bread with them for the journey.

It may seem odd that the most potent symbol of the most important Jewish festival is a kind of glorified water biscuit, but these little things often mean much more than might at first appear.

Passover is the great Jewish festival of nationhood and identity. And Jewish identity so often boils down to simple choices about what to eat. At my primary school — a state school in Hampstead Garden Suburb — the Jewish kids ate matzah during Passover and the non-Jewish kids didn’t.

For observant Jews, any contact with leavened material, or chometz as it is known, is forbidden. Jews are not supposed to allow even the merest crumb of old bread or biscuit to go anywhere near their food during the eight days of the festival.

Because of this, everything that might be consumed at Passover has to be specially prepared. Factories have to be specially cleaned and inspected by the rabbinate. For orthodox Jews, everything has to be kosher for Passover. This includes milk, butter, chocolate, tinned goods etc. Some Jewish shops will even sell kosher-for-Passover washing-up liquid and scourers.

Orthodox Jewish families will clean their houses thoroughly in the days before Passover. Jewish mothers are supposed to go into every little corner with a feather to remove the last vestige of chometz. In the London Borough of Barnet, where there are many Jews, the council even supplies skips so that families can throw out flour, biscuits, crackers and bread before the festival.

Jewish families will usually put away their ordinary crockery and pots and bring out special passover pots and plates. One house I visited even had its own Passover kitchen. The rabbi who owned it proudly removed a series of panels to reveal a sink and a small stove that were utilised only eight days a year.

Shortly before the start of Passover, the Jewish community launches into a buying frenzy. In addition to vast quantities of meat and vegetables needed for the family Passover meal, they buy eight days’ worth of matzah, special Passover cakes and all the food they need to get them through the week. At one shop I counted 14 kinds of matzah and 23 varieties of special kosher-for-Passover sauces, ketchups and salad dressings. Because many Jewish families don’t have enough Passover crockery to go round, they will often buy huge quantities of disposable cups, plates and foil trays, which are thrown away at the end of the festival.

These days many orthodox Jews, as a way of demonstrating their faith, will have special shmura matzahs. The word shmura comes from the Hebrew word to guard. The matzahs are specially watched from the time that the grain is harvested until the matzahs are cooked. Because the wet flour will start to rise to a small extent, even if it doesn’t have yeast, these shmura matzahs are cooked as quickly as possible after mixing.

In Stamford Hill in North London the community sets up its own bakeries for these matzahs. A few years ago I visited one, where young seminary students were furiously rolling out matzahs and throwing them into an oven. There was a party atmosphere, but it was done with serious intent.

The Passover festival celebrates the escape from Egypt. During the first night of Passover Jews traditionally hold a meal. Before the meal is served, Jews are supposed to recount the story of Passover and discuss its meaning. As children we used to spend the first night of Passover with my uncle, who was quite religious. He took so long going through the Passover service, that I would often fall asleep before we got to eat.

When I was a child, Israel and Egypt were still locked in a conflict that sporadically flared into war, as it did in 1967 and 1973. At a time when the very existence of Israel was in doubt, Passover had a very contemporary relevance.

To persuade Pharaoh to let the Jews go, the Bible says that God sent ten plagues. During the Passover meal Jews call down the plagues against Egypt. In those days, before the Middle East peace process had begun, when we cursed the Egyptians with blood, frogs, boils and pestilence, we really meant it.

It took Moses 40 years to get to Egypt. If you look at the map, it’s difficult to see why it should take more than a few weeks. Scholars have suggested that the Jews left Egypt as slaves. The time delay meant that by the time they arrived, a generation of slaves had died out and a nation of free people had taken their place.

Moses, of course, never got to enter the Promised Land. He could glimpse it only from afar before he died. Because he wasn’t born in freedom he could never enjoy its fruits.

Every year Jews around the Passover table raise a glass and toast: “Next year in Jerusalem.”

For most Jews this is not so much an outline of their travel plans as a way of affirming that they have remained true to their roots and to their sense of being part of one nation.