News that another of Norfolk's oldest and best established manufacturers is looking to leave the county has sparked questions over whether infrastructure in the area is to blame.

Heatrae Sadia, which is based at Hurricane Way in Norwich, announced this week that it is consulting with staff over a possible production move to Preston, putting 200 jobs at risk.

It is another blow to Norwich, where a further 300 workers will lose their roles this year when Britvic and Unilever, Colman's Mustard manufacturer, close.

The news has been slammed by Heatrae Sadia's employees' union, Unite, as 'cruel'. Heatrae Sadia has not yet given a reason for its move.

Steve Harvey, Unite regional officer for Norwich, said: 'Accessibility is one of the main reasons I can think of as to why manufacturers are leaving. Increased road and rail networks would definitely help.

'When you look at the main spine of the country north to south, the road networks are relatively good. Going east or west of that and the network isn't up to standard.

'Look at the A11, that's recently been dualled but it's still not fit for the amount of traffic travelling along there.'

He added: 'If companies are trying to use the excuse of accessibility to leave Norfolk, I'd tell them to look at Bird's Eye. Lowestoft is the only manufacturing facility in the UK and it's based right on the most easterly point.

'Perhaps we need to be asking these firms what is Bird's Eye doing, and what are they prepared to do to stay here, that you're not?'

Chris Starkie, chief executive of New Anglia LEP, said: 'Norfolk is a fantastic place to start, grow or relocate a company, with strong industry sectors, including manufacturing.

'With investment through our Growth Deal with government and work to secure national funding for a road and rail networks, we're also focussed on creating the transport infrastructure business needs to thrive.'

And Chloe Smith, MP for Norwich North, said: 'It's been the case for a long time that Norfolk transport is not good enough. That's why I and others have long campaigned, and with some success - such as the A11 and the [Norwich Northern Distributor Road] - for improved road and rail links.

'The vital next link is the A47 and I think it's very clear that Norfolk and Norwich would be a more attractive place for jobs and investment if people had more confidence in an east/west link.'

Our Just Dual It campaign has fought to the government fully dual the road by 2030.