Lindsay Sandiford, from Gloucestershire, was arrested in May last year as she entered Indonesia on a flight from Thai capital Bangkok with £1.6million worth of the Class A drug.
State prosecutors had called for the 56-year-old housewife to be jailed for 15 years but there was a gasp in the Bali courtroom today when she was told she would be killed for her crime.
Sandiford slumped back stunned as the judges announced the shock sentence which, if carried out, will see her led into an orchard where she will be executed by firing squad, blindfolded and tied to a pole.
Mrs Sandiford was heard to cry in anguish from under her beige-coloured sarong, marked with a traditional Balinese pattern.
She also wept and declined to speak to reporters on her way back to prison.
Mrs Sandiford had hoped she would be spared execution because of her age and for her co-operation with authorities on the holiday isle.
She had also claimed she was coerced into the crime because her children were threatened.
'We found no reason to lighten her sentence,' he said.
She will appeal within the next 14 days and her hopes of escaping the firing squad now depend on a series of legal challenges and, finally, with a plea for mercy to the president if all her legal channels become exhausted.
There are around 114 prisoners on death row in Indonesia, at least 40 of them foreigners, most of them convicted of drug crimes. Several are Australians.
Her demeanour suggested a woman in great shock - she spun about in the small cell for a moment or two as if uncertain what to do, before prison officers escorted her through a side door with other prisoners.
She was then driven to jail - and to an uncertain future.
On the face of it, bespectacled Mrs Sandiford, a mother of two who once worked as legal secretary, could not have been a more unlikely drugs courier.
After growing up in Cleveland, she moved to London where she married. She is now separated but has two sons, Lewis, 23, and Eliot, 21.
For some years Mrs Sandiford rented a £275,000 detached property in Cheltenham, Gloucestershire, where neighbours have less than fond memories of her.
Some have described her as a ‘neighbour from hell’. A man of 63 who lived next door said she was evicted around five years ago for failing to pay rent.
Even Mrs Sandiford’s mother, Audrey, refuses to have anything to do with her. She has lived abroad for many years and has remarried. She asked us not to reveal the place where she now resides.
‘I don’t go to England or have anything to do with Lindsay. I got tired of being a piggy bank and realised I was better off away from them,’ said the 86-year-old last June. She says she did not know Lindsay had been arrested and was ‘absolutely horrified. It’s a complete shock’.
Human rights charity Reprieve, which is assisting Sandiford, urged the Government to support her appeal.
Investigator Harriet McCulloch said: 'Lindsay has always maintained that she only agreed to carry the package to Bali after receiving threats against the lives of her family.
'She is clearly not a drug kingpin - she has no money to pay for a lawyer, for the travel costs of defence witnesses or even for essentials like food and water.
'She has co-operated fully with the Indonesian authorities but has been sentenced to death while the gang operating in the UK, Thailand and Indonesia remain free to target other vulnerable people.
'Lindsay must file an appeal within the next 14 days and it is vital that the British Government do everything possible to support Lindsay's appeal against the death sentence.
A spokeswoman for the Foreign and Commonwealth Office said this morning: 'We can confirm that a British national is facing the death penalty in Indonesia.
'We remain in close contact with that national and continue to provide consular assistance.
'The UK remains strongly opposed to the death penalty in all circumstances.'
Sandiford, originally from Redcar on Teesside, was one of a 'British gang of four’ who were caught and prosecuted after she tried to smuggle £1.6million of cocaine into the country from Thailand.
Sandiford had told her lawyer, Mr Ezra Karo Karo, that she believed she had been made the scapegoat because it was the other three members of the gang who had a bigger role in the operation than herself.
She immediately confessed that she had been told to hand over the drugs to Miss Dougall – and in a sting operation they followed her as she went about contacting Miss Dougall, Miss Dougall’s partner Julian Ponder, and Paul Beales.
But the case against Miss Dougall and Mr Beales started to crumble when police failed to find any physical evidence to connect Mrs Sandiford with the other three suspects.
Police sources said that all conversations between Miss Dougall and Mrs Sandiford were carried out through mobile phones. But police had failed to retrieve a SIM card during a raid on Miss Dougall’s Bali villa, meaning there was no physical evidence.