It was a total disaster at all the key levels of policy, organisation, personnel and message.

Ed Miliband is to be warned by senior Labour figures that he must work hard to fight a sense of complacency among many MPs after the party was rebuffed in Scotland and failed to make a breakthrough in the English local elections.

Shadow cabinet members were disappointed by results across Britain, with some saying the only hope was that the elections would jolt the party into appreciating the scale of the battle ahead.

The greatest blow came in Scotland where the SNP became the first party to win an overall majority in the parliament's 12-year history – a result widely described as an unmitigated disaster for Labour.

Miliband announced a review of the Labour party in Scotland as Iain Gray, its Scottish leader, announced he would resign in the autumn. "While we have seen good results today, gaining councils and councillors across England and winning in Wales, this is clearly a very disappointing election result in Scotland," Miliband said.

"We need to learn the lessons of that result, both political and organisational. That is why I, with Iain, am today putting in place a root-and-branch review of the Labour party in Scotland. This will bring together all elements of the Scottish party to renew it for the future."

One Labour source said: "It was a total disaster at all the key levels of policy, organisation, personnel and message."