ELECTION campaign adverts targeting Facebook users across Oxfordshire have been revealed for the first time.

New data shared with the Oxford Mail shows all the main political parties have been attempting to influence voters with the tailored messages.

It provides a rare insight into online campaign advertising, which is largely unmonitored despite the huge reach of Facebook.

This is because the social network allows ad buyers to target selected groups of people, with the ad then appearing on the newsfeeds of users – but not necessarily on public pages.

The data was released by Who Targets Me and the Bureau Local, part of the Bureau of Investigative Journalism.

Who Targets Me said it was part of efforts to bring 'transparency to political advertising on Facebook' and it is recruiting an army of web volunteers to help it.

The group said: "Targeted social media advertising is an important part of democratic debate.

"It can help people understand the adverts they see when they go online, and it will help make politicians responsible for what happens in digital campaigns.

"The more volunteers, the better the data, the more we can understand what political parties are getting up to on Facebook."

A sample of more than 200 ads were seen by 84 volunteers – aged 20 to 67 – in the Oxford East and Oxford West and Abingdon constituencies between April 28 and May 23.

They were bought by the Conservatives, Green Party, Labour and the Liberal Democrats.

Of those by the Conservatives that were seen by 50 Who Targets Me volunteers – mostly aged 20 – all made reference to Labour leader Jeremy Corbyn.

They variously described 'weak' Mr Corbyn's policies as 'nonsensical and dangerous', warned of the 'risk' he could become Prime Minister or drew a direct comparison between him and 'strong and stable' Theresa May as leaders of future Brexit negotiations.

Another 54 Labour ads – also seen mostly by users in their 20s – encouraged young people to register to vote and said the party's policies would be a 'fresh start' for Britain.

The small number of users in their 40s saw ads that instead talked about tax rises for higher earners and stressed there would be no extra taxes for the majority of workers – with two 60-year-old users warned that Theresa May was 'keeps changing her mind' about taxes and pensions.

The Liberal Democrats, meanwhile, had ads that were seen by 69 volunteers.

Those aimed at people in their 20s warned of Conservative plans to 'regulate the internet', 'poor' standards of housing and 'outrageous deposits' and also accused Theresa May of pursuing an 'extreme' and 'dangerous' Brexit plan.

Ads aimed at older users in their 60s promoted the Lib Dem policy of giving the public a referendum on a future Brexit deal and said doctors and nurses needed 'more support from government'.

Eight ads for the Green Party seen by users referred to its manifesto launch, plans to write off student debt, support for foreign aid and the BBC's decision to include UKIP in an election interview but not the Green Party.

Who Targets Me has appealed for more people to volunteer as data-gatherers during the election.

This is easy to do and requires downloading an extension for your internet browser, available at: whotargets.me/get-involved