Prime Minister Boris Johnson on Saturday vowed to press on with his post-Brexit agenda for Britain, even as the country faces a growing supply chain crisis made worse by its EU departure.

Rank-and-file members of Johnson's Conservative party gather from Sunday for their first in-person annual conference since 2019, after last year's event was forced online by Covid.

In a bullish eve-of-conference message to the Tory faithful, Johnson vowed to forge ahead with his post-Covid recovery plan to "build back better" in areas from infrastructure to climate change.

"This Conservative government has a track record of delivering on the people's priorities: we 'got Brexit done' and secured a deal with the EU -- keeping our election promise," he said of the Tories' landslide 2019 win at the polls and his Christmas Eve 2020 trade deal with Brussels.

But Johnson could face a torrid time, with his government under attack not just from the fall-out of his handling of the pandemic, but a slew of mounting problems from taxes to immigration.

The government has sought to blame the global health crisis for an exodus of foreign lorry drivers, adding to departures since Brexit took full effect and free movement ended in January.

Deliveries have been hit to supermarkets, making empty shelves an increasingly common sight, while a lack of tanker drivers triggered panic-buying, draining fuel at the pumps and forcing Johnson to call in the army to deliver stocks.

As Christmas approaches, there are warnings of a lack of supply of Christmas food, toys and turkeys, because of delivery issues and a lack of seasonal workers, many of whom previously came from Europe.

Johnson can point to a successful Covid vaccination roll-out, which was quick out of the blocks after vaccines were approved, and which has so far seen more than 82 percent of all over-16s double-jabbed.

But anger persists in some quarters at his handling of the pandemic and a high death toll of more than 136,000, as well as claims of cronyism for Covid contracts.

He has also risked the wrath of Tory colleagues for breaking an election pledge not to raise taxes, by announcing hefty new funding to fix a crisis in health and social care.

On Brexit, he has angered Brussels by threatening to shelve tricky new trading arrangements for Northern Ireland, and has delayed the full implementation of bureaucratic new border checks on imports from the bloc.

At the same time, he is facing criticisms for not doing enough to tackle growing numbers of migrants arriving on Britain's Channel coast from France.

Meanwhile, another storm is brewing with France after Britain refused many licence applications to fish in UK territorial waters.

On Saturday, protesters, some holding EU flags, gathered near the conference venue in Manchester, northwest England.

"Corrupt Tory government. Liars, cheats, charlatans. Get them out now," a banner read.

Last week, the main opposition Labour leader Keir Starmer attacked Johnson as a Brexit-obsessed one-trick pony without a plan, even if his popularity remains high with the public.

"Level up? You can't even fill up," said Starmer of Johnson's flagship economic policy.

"We have a fuel crisis, a pay crisis, a goods crisis, and a cost of living crisis, all at the same time."

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