Support for Malcolm Turnbull has significantly increased among voters, and he has increased his lead over Tony Abbott as the preferred Liberal leader, new polling from Essential Research finds.

And despite losing a leadership ballot to Julia Gillard, Kevin Rudd remains easily the most popular figure to lead Labor.

Turnbull’s rehabilitation in voters’ eyes over the past 12 months has been remarkable. In February 2011, he barely edged out Joe Hockey for second place as best leader 18% to 16%, well behind Abbott on 24%. By May, he had taken the lead as preferred Liberal leader, 25% to Abbott’s 22%. Today, 30% of voters prefer him as Liberal leader compared to 23%.

Turnbull’s rise has been propelled by Liberal voters — only 16% preferred him in February 2011, compared to 45% for Abbott; now 26% prefer him compared to 29% for Abbott.

Rudd remains easily the preferred Labor leader: last May 32% of voters preferred him; today 31% do. But Gillard has slipped from 23% to 16%, and “someone else” has gone from 19% to 23%.

Gillard still leads Rudd among Labor voters, however, 40-33%. The ferocious campaign of destruction launched at Rudd by cabinet ministers and the Gillard forces in the lead-up to Labor’s leadership ballot on February 27 appears to have done nothing to harm his popularity with voters. Bill Shorten is now the best of the rest, doubling his support from 3% to 6%.

On voting intention, the Coalition has picked up a point on its primary vote, to 49%, while Labor remains on 31% and the Greens on 11% — apparently unaffected by the departure of Bob Brown. That yields the same two-party preferred outcome as last week, 56-44%.

Voters also delivered a blunt message about the mining boom: 66% said they had received no benefit at all from the boom, with a total of 19% saying they had received a little, some or a lot of benefit. Thirty seven per cent of voters believe mining companies don’t pay enough tax, compared to 27% who think they pay the right amount (11% thought they paid too much).

Support for the mining tax remains relatively steady at 51%, down a point from March. But opposition has fallen significantly, down five points to 29%.