Four Calais hoteliers who filled their rooms with up to seven UK-bound migrants at a time were today facing prison sentences of up to five years.

Their trial in Boulogne-sur-Mer comes as the French authorities battle to keep the northern coastline free of asylum seekers who want to get to Britain.

More than 50 border police officers raided four hotels in Calais - the Pacific, the Citadel, the Bel Azur and the Tudor - on February 7.

The Bel Azur hotel in Calais was one of the four hotels raided by French border police

The four managers were arrested and accused of 'assisting in the stay of illegal aliens within an organised gang'.

They were allegedly working with a network of Albanian people smugglers who offered a guaranteed passage to England for between 5,000 euros (£4,300) and 10,000 euros (£8,600) per person, depending on the form of transport used.

It is alleged that lorries, vans and private cars were used and those who had paid the fee stayed in the hotels while they waited to be smuggled into Britain.

The hoteliers - a mixture of French and Algerian nationals - have been held in custody, and all deny the charges against them.

Calais remains a key transit point for migrants trying to get into Britain, even after the dismantling of the notorious Jungle camp last year (file photo)

Prosecutors claim the would-be asylum seekers were kept in filthy conditions in the budget hotels, with often with up to seven people in rooms with only one bathroom.

The arrests came as hundreds of migrants began returning to Calais following the closure of the Jungle refugee camp last October.

Around 8,000 men, women and children from countries as varied as Afghanistan, Eritrea and Syria were displaced to other parts of France when the shantytown was razed.

But police estimate there are up to 400 migrants now hiding in Calais and around 15 a day are arriving.

After more than two decades of Calais being at the centre of Europe's migrant crisis, the French are determined to maintain a zero tolerance approach to new arrivals.

Security has been stepped up around the Channel Tunnel, and in the port area, where ferries head to the South Coast ports of England night and day.

The four defendants first appeared at the Boulogne Correctional Court on February 10, and their trial is set to begin this afternoon.

All four were originally place in pre-trial detention, although two were released on bail last week.

Last year the Mayor of Calais, Natacha Bouchart, blamed the UK's 'black market economy' and 'cushy benefits system' for the thousands of migrants in her town.

She said: 'Calais is a hostage to the British. The UK border should be moved from Calais to the English side of the Channel because we're not here to do their jobs.'