He told MailOnline Travel: 'The pilot made an announcement requesting senior cabin crew, and we knew something was a bit odd.
"About 10 minutes later he said you may have noticed there's a quite pungent smell coming from one of the toilets.
"He said it was liquid faecal excrement, those are the words he used. He said it's not a technical fault with the plane, and he was very adamant about that.
The captain informed passengers that the plane's crew had examined the problem, but were unable to fix it.
He told them that the plane would be forced to return to London for health and safety reasons.
Passengers were initially told that they would board another flight in three hours, but it turned into a 15-hour delay, said Mr Sachdev, who was travelling with his pregnant wife, Rupa, and their two-year-old daughter, Shravani.
He said the airline offered an apology and provided hotel accommodation and food vouchers, but claimed BA ground staff were unprepared and told the travellers to contact the Civil Aviation Authority for compensation.
Mr Sachdev, who wasn't seated near the toilet in question, said passengers departed for Dubai yesterday at 1pm.
He said: "It's obviously disappointing to lose a whole day of your trip. You might expect it on some random airline, but you wouldn't expect it from British Airways."
After the plane landed at Heathrow, the councillor tweeted: "Insane! Our BA flight to Dubai returned back to Heathrow because of a smelly poo in the toilet! 15hrs until next flight."
A British Airways spokesperson told MailOnline Travel: 'We're very sorry for the discomfort to our customers.
"We provided them with hotel accommodation and rescheduled the flight to depart the next day."
- Daily Mail
