Sunna Wathan had opted for a home delivery

The drama began at 1600 BST on Tuesday when the London Coastguard received a 999 call from the houseboat.

Two midwives, who had previously been put on standby for the home delivery, were picked up at Tower Pier by lifeboat helmsman Stuart Richardson and his crew of two.

They were taken the short hop across the river to Butler's Wharf where the houseboat was moored.

Because of the height of the barge and the amount of equipment needed by the midwives, it was decided the porthole was the only way in.

'Piggyback'

After a safe delivery they went back at midnight to bring the midwives back.

Helmsman Stuart Richardson told BBC News Online: "The tide was low so we put the bow of the lifeboat on to the shore.

"Then we had to piggyback the midwives one at a time out of the porthole onto the the shoulders of crewman Kevin Maynard who was standing on the shore.

"It was probably just as strange a delivery for them as it was for us!"

The new lifeboats came into service in January

The crew went back to see the family and their new baby the next day.

Mother Sunna Wathan told them a name has not yet been chosen.

"She asked us to drop in for a coffee whenever we're passing," said Stuart Richardson.

The River Thames service is the first inland lifeboat service in England.

Four lifeboat stations provide a 24-hour rapid response from Teddington in the west to the North Sea.

The service was set up by the Maritime and Coastguard Agency and the Royal National Lifeboat Institution (RNLI).

It costs �1m per year to operate which is funded by donations.