As the nation reels from this week's shock general election result, party members of all stripes will be scratching their heads and asking themselves: 'How could this have happened?'

%image(14775280, type="article-full", alt="Chris Hanretty, University of East Anglia academic. Photo: Archant Library")

What factors managed to shrink a seemingly unassailable 20-point lead at the start of the campaign to the point where the Conservatives' opponents got to within a hair's breath of forming a government?

Many have placed the Conservatives' failure to secure an overall majority squarely on Theresa May's shoulders.

It was her and her alone who opted to call a snap poll three years before time on the basis that a stronger mandate was needed for Brexit negotiations - and a wish to quell the efforts of those she saw as trying to 'frustrate the will of the people' by challenging her approach to leaving the EU.

Many pointed to failures in her campaign, which was punctuated by social care taxation u-turns, lacklustre public appearances and robotic slogans.

%image(14775281, type="article-full", alt="Conservative Keith Simpson held his Broadland seat. Photo: Luke Powell")

Others put it down to Jeremy Corbyn's strong campaign and populist Labour party policies, such as dropping university tuition fees.

Dr Chris Hanretty, a University of East Anglia (UEA) lecturer and elections expert, said Brexit played a larger role in the result than many people imagined, particularly when it came to motivating pro-remain younger voters.

READ MORE: Norfolk and Waveney General Election Results 2017Dr Hanretty said: 'Initial survey estimates show the vote from the 18-25s was very much up on 2015.

%image(14775282, type="article-full", alt="Labour leader Jeremy Corbyn arrives at Labour Party HQ after he called on the Prime Minister to resign, saying she should "go and make way for a government that is truly representative of this country". Picture Dominic Lipinski/PA Wire")

'A lot of young people realised that if they had voted in the referendum the result might have been different.

'Also, young people have very concentrated distributions - they're clustered in particular parts of the country, so if words gets out it can have quite a big impact.'

Brighton Kemptown, Ipswich and Portsmouth South were among constituencies with high student populations that flipped from Conservative to Labour.

Dr Hanretty said he was, in fact, surprised that Mr Corbyn's popularity was not even higher, given his positive reception on the campaign trail.

He said: 'By the end of the campaign people preferred May to Corbyn in similar ratios that they preferred David Cameron to Ed Miliband.

'We can't say everyone's crazy about Corbyn, they're not, but they're more positive towards him now than they were four months ago.'

MP Keith Simpson, who retained the seat of Broadland for the Conservatives, said Mrs May's campaign performance had certainly played a role.

Mr Simpson said: 'She performed within her comfort zone. The way she was disposed during the campaign increasingly jarred with a significant section of public opinion.

READ MORE: UKIP see share of vote plummet in Norfolk and Waveney'Clearly her own authority within the Conservative Party has been badly shaken by this.'

Iain Simpson, who contested Broadland for Labour, said voters paid attention to different policies and voted accordingly.

Mr Simpson said: 'There was a huge amount of anger over the Conservative manifesto - dropping the pension triple lock and the dementia tax.

'You also had some Labour policies, in particular scrapping tuition fees, that were getting real cut-through on the doorstep.

'May didn't need to call the election and she made it very much about her. But the more people saw of her, the less they liked her.'

Amy Rust, campaigns and democracy officer for the UEA's student union, said universities, the media, as well as businesses and charities had all helped boost the number of younger people voting.

Miss Rust said while Labour's tuition fees policy was popular among students, it fed into a wider issue of rising costs of living.

She said: 'Labour had a fairly wide spread of policies - looking after the housing market and improving access to education.

'The Conservatives and Lib Dems really just had single education policies which didn't relate to how students are feeling at the moment.'

Miss Rust said the rise of social media also played a part in raising awareness of politics, among young people in particular.

She said: 'Politics is now there, day to day in people's lives.'

Cliff Jordan, the Conservative leader of Norfolk County Council, said: 'People didn't like some of the policies that came out of the manifesto. We saw older people getting upset about their winter payment. The Conservative campaign was poorly run.'