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Videos about the NHS were the most viral posts on social media during the 2019 general election campaign.

Four of the most viewed and shared videos on Facebook, Twitter and Instagram were about concerns regarding funding and staff levels in the NHS. Political parties, particularly Labour and the Conservatives, focused their digital campaigns on the production of controversial and humorous videos, using elements of pop culture in order to rack up shares.

We checked video views and shares on Facebook and Instagram using CrowdTangle, a Facebook-owned social media analytics tool that tracks and records public data from Facebook, Instagram and Reddit. We also used Khoros to track data from Twitter.

We looked at videos posted between 29 October - the day the election was called - and 11 December, the last day of campaigning. We've only tracked the number of views up until the 11th. Here are some of the most viewed and shared videos of the campaign.

1. Joe Politics video on US healthcare cost

The Joe website, which has a history of producing viral political videos, approached members of the public on the streets of London with questions about the average cost of calling an ambulance, buying an inhaler or giving birth in the US. Its video captured the shock on people's faces when they were told the actual costs.

It was immediately picked up and shared by US Democratic presidential candidate Bernie Sanders and Representative Alexandria Ocasio-Cortez, who both want to see an overhaul of the US healthcare system into a single-payer system known as Medicare for All.

The video has racked up 39.5 million views in total on Facebook and Twitter, making it the most viral piece of digital content in the campaign.

Although many of those views will undoubtedly have come from the US, no other video in this campaign has achieved similar numbers.

2. 'How many nurses?'

Culture Secretary Nicky Morgan, who was not standing in the election, faced questions about a Conservative manifesto pledge to recruit 50,000 more nurses in England by 2024-25 during an interview on ITV's Good Morning Britain. She was pressed by presenters Piers Morgan and Susanna Reid on whether 19,000 of those would be existing nurses. A clip of the interview later appeared on Channel 4's Gogglebox and drew funny reactions from the participants.

Both the campaign group Momentum, which is linked to the Labour Party, and Jeremy Corbyn's Facebook account shared versions of the interview with their followers, with the question, "how many nurses?".

The various versions of the video have 13.8 million views in total on Facebook and Twitter.

3. Rob Delaney's support for the NHS

UK-based American comedian and actor Rob Delaney, who is a vocal Labour supporter, featured in a party video about differences between the NHS and the private insurance healthcare system in the US. Mr Delaney compared his experience in the US, where he faced a hefty bill for surgery following a car accident, with the way his deceased son Henry was treated by the NHS for a brain tumour.

The video was posted on Mr Corbyn's Facebook and Twitter accounts, and has been viewed more than 13 million times.

4. Boris Johnson's reaction to sick boy image

Four-year-old Jack, who had suspected pneumonia, was forced to sleep on the floor of a Leeds hospital because of a lack of beds. Initially reported by the Yorkshire Evening Post, the story became a campaign talking point after ITV News political correspondent Joe Pike asked Prime Minister Boris Johnson to look at the photo of Jack on his phone. Mr Johnson initially refused to do so and put the journalist's device in his pocket.

Mr Pike posted the video on Twitter, where it was immediately seized upon by Labour, who posted it on Mr Corbyn's Facebook and Twitter accounts.

It received more views the next day after a number of misleading claims on social media suggested the photo was staged.

The video has so far received just over 13 million views.

5. Andrew Neil's interview challenge

Last week the BBC's Andrew Neil issued a direct challenge to Mr Johnson - the only leader of a main party not to have sat down across from him for a half-hour, prime-time grilling - to take part in an interview. "It is not too late. We have an interview prepared. Oven-ready, as Mr Johnson likes to say," Mr Neil said in a monologue:

The video, which was posted on social media by BBC Politics, has had 9.7 million views in total.

6. Corbyn's 60-second policy challenge

On the day Labour launched its manifesto, Mr Corbyn published videos of himself summing up some of its most prominent policies in 60 seconds.

The format was made popular in early November by New Zealand Prime Minister Jacinda Ardern, who was given a challenge to sum up her first two years in office in two minutes.

Mr Corbyn's summary received 6.5 million views in total.

7. 'His fault'

A politician faces angry questions in a public meeting, including a mother about her daughter's school, a man about her mother's waiting time for surgery and a young woman struggling to pay rent.

"It's all his fault," says the politician repeatedly in response, while pointing at an immigrant sitting at the back. This Labour video is about politicians who "resort to blaming immigrants".

It has 6.5 million views in total.

8. Johnson's tea break

Early in the campaign, the Tories posted an unexpected video of their leader answering a range of political and non-political questions during a tea break. Mr Johnson was asked about issues ranging from the election and the biggest challenge facing the country to his favourite food (Marmite) his cooking abilities and his favourite band.

It may have raised eyebrows initially, but the video successfully caught the attention of social media users, racking up 5.7 million views in total.

9. 'Brexit, actually'

With only a few days to go before polling day, Mr Johnson's social accounts posted a video of him recreating an iconic scene from the 2003 British Christmas-themed film Love, Actually. In the original, Andrew Lincoln holds up placards to Keira Knightley to declare his feelings for her. In the election version, Mr Johnson holds up placards centred around his campaign theme of "get Brexit done".

The video has received five million views in total so far.

10. Corbyn reads mean tweets

"Celebrities Read Mean Tweets" is one of the most popular segments of US comedian Jimmy Kimmel's late-night TV show. In it, Hollywood stars and celebrities are asked to read out and respond to insulting tweets about themselves. In a light-hearted video made by Labour, Mr Corbyn is asked to do the same.

The video has received 3.4 million views in total.

How many views did the parties get overall on social media?

Using the social media analytics tool CrowdTangle, we looked at the performance of parties and party leaders on Facebook and Instagram from 29 October to 11 December.

Despite losing the election itself, on Facebook, Labour won the video battle with 16.8 million video views from 186 videos posted by its official account. The Conservatives were a close second on 15.8 million views from 192 videos.

Other parties were way behind Labour and the Tories.

Looking at party leaders' Facebook accounts, Mr Corbyn was the clear winner with 72.3 million views from 192 campaign videos, while Mr Johnson's account racked up 14.4 million views from 137 videos.

The numbers are much lower on Instagram.

Labour achieved 1.2 million views throughout the campaign, with the Conservatives on 592,000.

Mr Corbyn's account received 5.5 million views, while Mr Johnson's had 1.1 million in total.

Once again, other parties and leaders were nowhere near the two main parties.