Hacking collective Anonymous has launched a cyber attack against the Thai police over the conviction of two Burmese migrants for the murder of Norfolk student Hannah Witheridge and fellow backpacker David Miller.

The digital activist group, known for taking websites off-line, posted links to 15 Thai police websites, including the Bangkok Metropolitan Police Bureau, and published several Thai police email addresses, asking its members to hack them, national media are reporting.

The attacks were carried out after a 37 minute video was posted on Anonymous's Facebook page.

It said 14 websites had been targeted and a masked person questioned the competency of the Thai police force and its handling of the murder investigation and other cases.

'We do not like the facts in this recent Koh Tao case and we do not believe the Thai court has convicted the actual murderers,' the figure said, in a digitised voice.

The words 'Failed Law', 'We Want Justice', and a hashtag #BoycottThailand were displayed on some of the hacked sites, along with the name of the Myanmar-based 'Blink Hacker Group'.

Thai police have confirmed the attacks but insist no confidential data has been taken.

Two Burmese migrants were found guilty and sentenced to death on Christmas Eve for the brutal double murder.

The bodies of Hannah Witheridge, 23, from Hemsby, and David Miller, 24, from Jersey, were discovered on a beach on the holiday island of Koh Tao on September 15 2014.

Zaw Lin and Wai Phyo, also known as Win Zaw Htun, initially confessed to the killings but later retracted their statements - claiming they had been tortured by police.

As the judge read out the verdict the mothers of the two convicted men collapsed, and their sons cried.

Prosecutors said DNA evidence found on cigarette butts, linked the men, both from Myanmar, to the killings.

Their account was disputed by the defence team who said evidence was mishandled by police and that the case had been dogged by chaos and error from the start.

The guilty verdict also sparked angry protests in Myanmar.

Anonymous are a loose group of 'hactivists' formed in 2003.