Leanne Wood, the leader of the Welsh nationalists Plaid Cymru, is by far the most popular of the main party leaders in Wales, according to a poll.

The polling, which comes at the start of the last full week of campaigning before next week’s assembly election, suggests Plaid could end up being the second biggest party, behind Labour but ahead of the Tories.

Wood, a former probation officer, was one of the star performers during last year’s UK general election campaign, winning fans for slapping down Ukip’s Nigel Farage during a leaders’ debate.

The poll, carried out by YouGov for ITV and Cardiff University’s Wales Governance Centre, asked voters if they felt the leaders were doing well or badly.

Taking the percentage for “badly” away from the percentage for “well” put Wood at the top of the table on 16%. The first minister and Labour leader, Carwyn Jones, was on 4%. Farage and the Ukip leader in Wales, Nathan Gill, were on -16% while the prime minister, David Cameron, was -37%.

The polling has Labour winning 28 of the 60 seats – down from 30, which would probably leave it needing a coalition partner if it is to remain in government. Plaid is predicted to win 13 seats, the Tories 10 and the Lib Dems two. Ukip, which has never won a Welsh assembly seat, is projected to win seven.

Plaid is buoyed by the findings. Its shadow economy minister, Rhun ap Iorwerth, said: “This is an encouraging poll for Plaid Cymru and shows that we have momentum going into the final days of the campaign. We are delighted that the warmth, respect and affection we’re experiencing for Leanne Wood on the doorstep is reflected in this poll, which gives her a clear lead as the most popular party leader in Wales.”

The steel crisis at Port Talbot and the Panama Papers have made this a very difficult campaign for the Tories, who tried to play down the poll’s findings.

A Welsh Conservative spokesperson said: “Voters across Wales will know that after 17 years of Labour, the only way to secure real change is to vote Welsh Conservative. Polling 12 months ago proved to be well wide of the mark, and voters increasingly take these snapshots with a large pinch of salt.”