Labour will attempt to move beyond the turmoil of its leadership contest by commiting to guarantee almost £10bn of EU funding to deprived regions if elected.
Shadow foreign secretary Emily Thornberry was to announce plans for a fully protected fund to substitute for the lost EU schemes at her party's annual conference in Liverpool, with the backing of shadow chancellor John McDonnell.
She planned to tell delegates how the fund will be a "central plank" of Labour's manifesto for the next general election and will be the party's top priority for savings achieved from EU withdrawal.
Ms Thornberry planned to say: "Without long-term certainty over funding, our most deprived regions and communities cannot plan ahead. They cannot attract other investment. They cannot make progress.
"So thanks to John McDonnell, Labour's shadow chancellor, we can guarantee that a future Labour government will make up any shortfall in structural funding into the 2020s and beyond."
She added: "The communities who stand to lose out most from Brexit must be looked after first."
The promise guarantees that future Labour governments will match all EU structural funding currently worth £9.3bn from 2014 to 2020.
Regions likely to benefit most from the scheme would be Wales, which is allocated £2.1bn under the current seven-year programme, the South West, which is due to receive £1.3bn and the North West, with an allocation of £979m.
Meanwhile, Mr McDonnell will promise Labour will offer an "interventionist government" prepared to protect key British businesses from global market pressures.
The shadow chancellor will use his keynote speech to herald a post-Brexit "manufacturing renaissance" backed by a comprehensive industrial strategy under Labour.
