UK survivors of the Asian tsunami have criticised British embassy officials for their initial handling of the disaster, in a new independent report.
More than 200,000 died in the tsunami on 26 December, 2004
Some survivors said UK officials they dealt with were "superior", unhelpful, and out of their depth.
Foreign Office minister Lord Triesman said measures had been put in place to tackle problems raised in the report.
More than 200,000 people died - including 151 Britons - when the tsunami struck on December 26 2004.
Hundreds of thousands more managed to escape, with many badly injured and in shock.
The countries hit included Thailand, Sri Lanka and Indonesia.
A review by the National Audit Office (NAO) reveals the experiences of UK tourists who survived and those at home trying to find out about loved ones.
In compiling the report, 116 people were interviewed by the Zito Trust, which supports families who lose a relative in sudden circumstances.
A number of those spoken to, who have not been identified, outlined grievances with British embassy officials.
One respondent wrote: "British consulate members were on holiday in the area.
"After the tsunami they sat in our guest house which was just out of reach of the tsunami, they didn't help anyone in any way, they sat there and got drunk until a minibus they called for arrived.
Survivors praised officials after they revisited tsunami-hit areas
"When it arrived they didn't offer anyone else a lift to a safe area, they just left.
"Their conduct was disgraceful and made me ashamed to be British."
Another survivor recalled: "[I suggest we need] better trained professional British embassy staff who do not treat the public as idiots and get rid of that superiority."
One survivor added: "They were out of their depth and totally overwhelmed."
Others criticised the lack of information UK officials provided, saying not enough British advertisements giving advice were placed in local newspapers or on TV and radio.
Respondents also found the national missing persons hotline was overloaded, with many relatives unable to get through in the first few days.
The survey found that as time went by UK officials started to cope better and they were praised for the assistance they gave when people revisited the area.
"Nothing was too much trouble. The level of care and attention provided to support this difficult journey was remarkable," one respondent said.
Overall the NAO said UK agencies were initially "overwhelmed" by the sheer scale of the tsunami and did not have a plan for responding to such a challenge.
The report listed a number of recommendations, including broadening the training and assessment of staff likely to deal with traumatised people and improving data gathering and sharing between agencies.
Lord Triesman said a number of measures had already been put in place to tackle problems raised in the report.
"The sheer scale of the 2004 tsunami meant that no organisation was able to respond as it wanted," he said.
"As a result, some UK families and individuals did not get the support they could have expected to receive."
The new measures include establishing support networks in the UK, improving call-handling capacity, building regional rapid deployment teams and improving volunteer training.
The government has agreed to respond to the report with an overall action plan within six months.