In the busiest week of the year for British holidaymakers heading for South Africa, an average of 10 families a day are being denied boarding when they turn up at Heathrow. They fall foul of draconian new rules that demand a full birth certificate for each child.

Grant Hughes, an account manager from Suffolk, was booked to fly from Heathrow to Addis Ababa and onwards to Durban with Ethiopian Airlines. Mr Hughes, 45, was travelling with his fiancee and his two children, aged 11 and 15, for their wedding in the city on 16 December. But the airline, which had not told them birth certificates were obligatory, refused to let them board the plane.

Responsibility rests with passengers to ensure they have the necessary documents to enter a country. Airlines face fines from the South African authorities if they carry passengers under 18 who do not have a birth certificate and are therefore inadmissible.

“I would have accepted it had it just been me who had made an oversight,” said Mr Hughes. “However we were told that this is a regular occurrence and roughly 10 families a night are being turned away due to this across various airlines.”

The onerous new rules were imposed in June as“New immigration laws to protect citizens and to improve lives”. The intention was to tackle child-trafficking. But with thousands of British travellers flying to South Africa for Christmas, the unintended consequence is to ground hundreds of families who have booked South African holidays costing thousands of pounds.

Protest on runway at Heathrow

David Frost, Chief Executive of the Southern African Tourism Services Association, said: “It’s an appalling way to behave when we should be doing everything to foster tourism. With the Rand so favourable, we should have been growing at double digits, but out of the UK we have been basically flat.”

Mr Frost said that on a typical long-haul flight departing for South Africa, between 10 and 20 people are being denied boarding.

British Airways, South African Airways and Virgin Atlantic, which fly direct from the UK to Johannesburg and Cape Town, say they do all they can to inform passengers about the new rules. BA has emailed all customers who have travelled to South Africa in the past year, as well as those with advance bookings.

The majority of denied-boarding cases known to The Independent involve passengers who book through online travel agents for airlines that do not fly direct.

One leading travel-industry figure, who did not want to be named, said: “South Africa looks intent on shutting down family tourism. Kenya and Tanzania can’t believe their luck - this is the best promotion they’ve ever had.”

Mr Hughes said: “We have now managed to arrange a flight to South Africa through some fine jiggery pokery by a travel agent.” He has spent £6,500 on new tickets, and is flying out with his family this morning via Paris and Johannesburg.