Organisers of a convoy from Norfolk taking supplies to migrants camped near Calais have today vowed to go ahead with the mission – despite French authorities saying they will be turned away at the border.

Two minibuses stocked with donations were due to set off from Norwich on Saturday morning and join up from other groups elsewhere from across Britain to drive to the ferry terminal in Dover.

However yesterday the French Border Police banned the convoy. Months in the planning, more than £2000 has been raised and rucksacks full of vital donations have been collected.

There are 26 volunteers from across Norwich determined to make the trip.

Julie Bremner, a member of Stand up to Racism Norwich, who is taking part in the convoy, said: 'It isn't going to stop us. We will still go and will travel to Dover as we had planned and get as far as we can go. Hopefully the pressure of 250 vehicles will make them change their minds. When we are on there doorstep, wanting to help people who are hungry, thirsty and cold, how can they turn us away?'

Stand up to Racism Norwich and The Ihsan Mosque, near Chapelfield, have arranged for a minibus each to take part. The party will leave the Theatre Royal at 9am.

Jean Thirtle, a senior steward at Unison Norfolk, said: 'We are facing the largest humanitarian crisis of the 21st century and cannot turn our backs on these desperate people.'

In less than an hour, a petition calling for David Cameron to intervene in the situation, received more than 500 signatures.

The convoy is supported by various organisations including Unison, the Muslim Association of Britain, Momentum and Unite.

One of the vehicles scheduled to travel to Calais is a 38-tonne truck.

On the Stand up to Racism website, a statement says: 'The convoy is going to go to Dover whatever happens. We will be calling on all our supporters to turn up in Dover and demand that we are allowed to get on the ferry we have booked and paid for.

'We are calling for a mass protest at this undemocratic and authoritarian decision, we demand that the British government tell the French authorities that this is unacceptable and that we should be allowed free passage.'

A press conference is being held today at the storage facility housing donations. At 11am people will gather at Access Self Storage, in Kings Cross, in London.