Media playback is unsupported on your device Media caption About 50 migrants managed to get on the P&O ferry bound for Dover

The French government has promised to keep law and order in Calais after migrants stormed a UK-bound ferry.

Interior minister Bernard Cazeneuve said 35 people - 26 migrants and nine activists - were arrested during the incident on Saturday.

He said mobile forces, including riot police, gendarmes and border units, had been mobilised for several months.

It comes as the UK Road Haulage Association called for more "decisive action" to secure the port.

Chief executive Richard Burnett said France should deploy its military to guard the area warning it was "only a matter of time before our worst fears become a reality and a UK-bound truck driver is killed".

Mr Cazeneuve was speaking after local politicians in the Calais area voiced anger at the law and order situation.

Calais mayor Natacha Bouchart said at a news conference that she accepted the humanitarian point of view but not "this anarchic situation". Regional president Xavier Bertrand called for an urgent crisis meeting to be held, and said that every day military reinforcements became more indispensable.

But in a statement the interior minister said the country's government had a "total determination" to maintain law and order.

He said significant work had been done around the Channel Tunnel and ferry terminal with the help of the British authorities to prevent disorder while accelerated asylum procedures had helped reduce migrant numbers at Calais from 6,000 to 4,000 in recent months.

The port in northern France was closed for a time on Saturday and services were disrupted overnight after about 50 migrants briefly boarded P&O's Spirit of Britain ferry.

The incident happened during a protest at the port in favour of migrants.

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Mr Burnett said: "This shocking breach of security clearly shows that the migrant mayhem in and around Calais is not being tackled.

"It is now time for the authorities to acknowledge and meet our demand for the French military to be deployed to secure the port and its approaches."

He added: "The number of migrants in the camp has escalated, the number of attempts - violent attempts against drivers - has been escalating, and we think now, after yesterday's incident, enough is enough, the time for discussion's over - we need action."

Damian Collins, Conservative MP for Folkestone and Hythe, backed Mr Burnett's call, telling the BBC it was "incumbent on the French authorities to protect the port".

"If that requires deploying the military, then the French should do that," he added.

P&O Ferries tweeted that services on Sunday were "operating to schedule", following delays of up to two hours on Saturday night.

Image copyright Getty Images Image caption Around 2,000 are thought to have been at a pro-migrant demonstration on Saturday

The latest incursion happened as a demonstration, held in support of migrants, was reported to have attracted a crowd of about 2,000 people.

Some of the protesters at the demonstration carried banners saying "refugees welcome here". People from Britain were among the demonstrators.

It comes as thousands of migrants are currently living in camps known as "the Jungle" on the edge of Calais.

The population of the camp has risen steadily in recent weeks to about 2,500, including about 250 children, according to medical volunteer group, Medecins Sans Frontieres‎.

In August last year, the UK and France signed an agreement on new measures to try and alleviate the crisis, including a new command centre to help tackle trafficking gangs.

The situation in Calais comes amid an influx of migrants to Europe - caused largely by people fleeing war and oppression in countries such as Syria, Afghanistan and Eritrea.

Elsewhere on Saturday, Jeremy Corbyn visited a migrant camp in northern France and spoken of the "dreadful conditions" there.