The Best For Britain anti-Brexit group has this weekend launched a £250,000 pro-EU blitz.

Best For Britain said its new campaign will do what the official Remain campaign and other anti-Brexit groups have failed to do and make a positive case for the UK's EU membership.

It has been funded partly by a sharp increase in small donations since Prime Minister Boris Johnson's controversial move to suspend Parliament, insiders said.

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Boris Johnson's controversial decision to suspend Parliament led to a spike in small donations to one of the leading campaign groups against Brexit.

The prime minister's move to shut down Parliament for five weeks in the run-up to the October 31 Brexit deadline, triggered large public protests and will be subject to legal review this week by the Supreme Court.

It has also triggered a surge in small donations to anti-Brexit campaigners, with the Best for Britain group telling Business Insider it has seen the number of small donations more than treble in recent weeks.

The group will this weekend use this cash influx to fund a quarter of a million pound advertising blitz, which it says will make the positive case forthe United Kingdom's membership of the European Union.

The group says its Where We Stand campaign will "make the positive case for Europe which the official 2016 Remain campaign, and all other national anti-Brexit campaigns since, have shied away from."

With a snap general election expected to take place before the end of the year, Best For Britain is working on strategies for getting as many pro-EU, pro-referendum members of Parliament elected to the House of Commons as possible.

For a number of weeks it has been engaged in discussions with other pro-EU groups and opposition political parties which are opposed to Brexit, about working together at the next general election.

These discussions have included Unite To Remain, the cross-party group set up by independent MP Heidi Allen, which is working on arranging electoral pacts across the country. It is close to publicly revealing the first batch of seats where it has finalised electoral pacts, two sources familiar with the group told Business Insider.

It also understood that Best For Britain has renewed close ties with the campaigner Gina Miller, who has fronted the legal case against parliament's suspension in the Supreme Court. Miller co-founded the group in 2017.

Making the positive case for continued EU membership

Best For Britain hopes its new campaign will persuade middle-ground voters who are neither ultra-Remain or steadfast Brexiteers, to support the UK staying in the EU.

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A Best For Britain insider said Where We Stand will be "less shouty" than other anti-Brexit campaigns, and focus on where and how EU membership has benefitted Britain, rather than adding to economic warnings about a no-deal Brexit.

Such middle-ground voters "are the people who will win or lose this for either side," they said.

The campaign will make the positive case for continued membership by highlighting EU investment in schemes such as the Eden Project and the Wildlife Trust.

The group has also produced social media videos and leaflets and plans to make a mark at Conservative party conference in Manchester next week by projecting advertising onto the city's notable landmarks.