More than 30 would-be illegal immigrants have been found hiding in four lorries in Calais, waiting to cross to Dover.

The discoveries were made by Border Force officers within 24 hours of each other and involved Albanians, Afghans, Iranians, Pakistanis and a Syrian.

It happened on Wednesday and started when, in the early hours, a sniffer dog indicated that there were people inside Turkish-registered lorry being driven by a Turkish driver. The vehicle, which was heading to Peterborough, was searched by officers who found 12 Albanians concealed in the load of mixed goods.

Officers using heartbeat monitors also discovered six Afghans hidden in a Polish-registered vehicle, driven by a Polish national, laden with sofas en-route for Accrington.

Later the same morning a second indication by a detector dog, this time on a Czech-registered vehicle, led officers to find six Albanians hidden in a load of nappies bound for Barton-upon-Humber, Lincolnshire.

The fourth discovery was in an Irish-registered lorry heading to the Republic of Ireland laden with mixed goods.

Following a positive indication by a dog the vehicle was searched and seven people - three from Iran, two from Pakistan, one from Afghanistan and a Syrian - were found in the load.

All the stowaways were handed over to the French border police and the vehicles allowed to continue their journeys.

Paul Morgan, Border Force director for the south east and Europe, said: "This incident shows why we base Border Force staff in France - to stop would-be illegal immigrants before they reach our shores.

"Our strong presence in French ports like Calais and close collaboration with the French authorities helps protect the whole of the UK from people attempting to enter the country illegally.

"As well as using sniffer dogs, officers also use heartbeat detectors, carbon dioxide probes and physical searches to find people hiding in vehicles".