YouGov president Peter Kellner says Labour leader Ed Miliband will be the next prime minister, despite his party winning fewer seats than the Conservatives. He thinks the Tories will win 280 seats compared to Labour’s 270, but will not be able to find viable coalition partners.

Speaking at SUMMIT, an event discussing entrepreneurs and future growth in the UK, Kellner admitted, “This is the most uncertain election that I can recall”. But he added: “At the moment, I think we’re heading for a really quite interesting and fraught outcome in which the Conservatives will have more seats than Labour, but not enough to carry on in government.

“David Cameron needs close to 300 seats to be certain to get enough votes to remain in government. If they’re at 280, there’s no way they can put together enough votes to remain in government. If the Conservatives are on 280 seats, Labour will be arithmetically around 270 seats and if that’s where we end up, the Tories cannot technically remain in government.”

Turning to the question of EU membership, Kellner said the UK would not vote to leave the bloc in a referendum. A vote on EU membership is mandatory if the Tories are returned to government, but he calculated only a 5% chance of the country voting for an exit.

At the same event, held at Bloomberg’s London headquarters yesterday, Goldman Sachs Jim O’Neill poured cold water on the notion that immigrants are harming the UK, a major bone of contention between the parties in the build-up to polling day.

He pointed to the success of global technology brand Apple in places like China, claiming that its recent strong results have been powered by the “demographic spread of its employees”.

For those of you who missed it, here are the day's highlights from #summitgrowth https://t.co/W1jBQuJnvn

— Seven Hills (@sevenhillsviews) April 29, 2015

Separately, he called on politicians to keep pushing the Northern Powerhouse agenda, a leading Tory policy to drive connectivity and growth in Northern cities such as Manchester, Liverpool, Leeds and Sheffield. He said it could boost UK growth by 0.2% a year.

"I don’t understand why the Northern Powerhouse hasn’t featured more in the coalition, because it seems to be working. It could push our growth rate two tenths of a percent. We’ve got to make sure the Northern Powerhouse keeps momentum.”

Another speaker, Autonomy founder Mike Lynch warned that Britain was losing its top tech talent to Silicon Valley in the US.

He said: “We are still turning out the best technologists in the world. However, rather like other countries that have vast oil reserves in the ground, we’re not very good at extracting that.”