A majority of Britons support the "targeted killing" of terrorists, both overseas and at home, according to a YouGov poll.

The survey, carried out for the defence policy thinktank RUSI and launched in London on Tuesday, finds 54% of the public support assassinating individual terrorists abroad, against 31% who object. Killing terrorists in the UK is backed by 52%-34%. An even more decisive 57%-29% supports the targeting of kidnappers and pirates.

Half a century on from England's last hangings, the survey will alarm human rights campaigners, who regard state-sponsored assassinations as extrajudicial executions. But the public's approach is not uniformly trigger-happy. Britons are split strongly against assassinating the scientists working on Iran's nuclear programme, by 56%-26%, and would oppose an attempt to kill Syria's president, Bashar al-Assad, by 49%-27%.

There are interesting variations in support for assassinations across the population – women and younger voters are notably less enthusiastic. In the case of pirates and kidnappers, for example, only 47% of women favour targeted killing, as against 67% of men; and 37% of people aged 18-24 are in favour, against 64% of those aged 60 or over.

Assassination support chart Photograph: Graphic

The survey focuses on reports that the UK has been passing information to the US to help them carry out "drone" attacks to target people deemed terrorists in countries such as Pakistan, Yemen and Somalia. Britons are split over whether such attacks make the west safer – 32% believe that drones bolster security by facilitating the targeting of terrorists, whereas 31% calculate that – by turning local opinion against the west – security is undermined.

The study uses follow-up surveys to test how changing the circumstances alters attitudes to UK assistance in this sort of US mission. By 55%-23%, respondents support British assistance with a US drone attack on "known terrorists". Support for the attack rises to 74% when a sub-sample was told the attack could prevent an imminent terror attack against the UK, and it scarcely falls back when a separate sub-sample is told the prospective target in the same circumstances is a UK citizen, remaining at 71%.

Support rises further, to 75%, when another sub-sample was asked to imagine that "it were guaranteed that no innocent civilians would be killed" by an assassination that could scupper a plot against Britain.

More striking is respondents' readiness to accept civilian casualties in the context of an immediate terrorist threat: 64% of one sub-sample would continue to back the drone strike even if it were likely that two or three innocent civilians would be killed, and 60% of another random sub-sample would back the attack even if 10-15 civilians were killed.

Elsewhere in the study, there is evidence of a generally favourable view of the military potential of drones, albeit tempered by a few doubts. By 57%-11%, Britons say drones "can reduce casualties by removing the need to send in people on the ground", and – despite recent debate about drones going awry and killing civilians – by 47%-13% people are inclined to believe that the accuracy of drones reduces so-called collateral damage. By 25%-24%, they narrowly reject the suggestion that drones cause more civilian damage than other long-distance weapons.

By 61%-6%, drones are approved of "as a useful tool for gathering intelligence", and yet there are misgivings about the life-and-death power they concentrate in the hands of western leaders. By 39%-15% voters, agree that drones give "too much personal power to pick and choose who is killed" and, by 47%-13%, they also worry that the technology "makes it too easy for western governments to conduct military strikes in foreign countries".

The YouGov study included six surveys between 26 February and 8 March, with a nationally representative poll of 1,966 British adults and several survey experiments looking at different scenarios, involving at least 700 respondents in each case.