They are still refugees.
A refugee is a person who ‘owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group, or political opinion, is outside the country of his nationality, and is unable to or, owing to such fear, is unwilling to avail himself of the protection of that country…’(Definition quoted from the 1951 Refugee Convention)
Legally, an asylum seeker is a person who has applied for asylum in the UK and is waiting for a decision on his or her claim. A refugee on the other hand has already received a positive decision from the authorities on his or her asylum claim. So, strictly speaking the migrants in Calais are neither refugees or asylum seekers from a UK legal perspective – at least as long as they remain in French territory.
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However some of the will be economic migrants.
The term economic migrant is often confused with the term refugee, but economic migrants leave their country due to bad economic conditions, not due to fear of persecution on the basis of race, religion, or ethnicity.