Only 23 per cent of Germans believe that the government will meet this goal, the poll by YouGov found, while 62 per cent are sceptical.

Fifteen per cent were undecided.

Merkel has repeatedly underlined her aim to offer all adults the jab against Covid-19 by September 21, although trust in this promise has faltered amid Germany’s sluggish rollout of the vaccine.

A similar poll carried out in early February found 26 per cent still believed the target would be met, while 57 per cent did not believe this was likely.

Even among voters for Merkel’s Christian Democrat party (CDU), many question whether the goal can be met, with 53 per cent of voters for the CDU and its sister party, the CSU, doubtful.

Levels of doubt are even higher among supporters of other parties.

Some 61 per cent of voters for the Green and Left parties say the goal is unrealistic, as do 63 per cent of Social Democrat voters. The levels are even higher among the pro-business FDP at 73 per cent and 82 per cent among the far-right AfD.

Germany’s inoculation campaign has been far slower than many other countries but this month some 35,000 family doctors are due to start giving vaccines, accelerating the process. Later, medical specialists, private physicians and company doctors will also help to speed up the efforts.

Meanwhile, people’s willingness to receive a vaccine has fallen slightly since a similar survey in January, when 67 per cent of respondents said they wanted a jab. That proportion has fallen slightly, to 57 per cent plus 8 per cent who have already received the vaccine, adding up to 65 per cent.

Eighteen per cent did not want to receive a vaccine, while 16 per cent were undecided.

The survey was carried out between February 3 and 5 and 2,077 people were polled. The results were weighted and are representative of the German population over 18.