DOVER, England (Reuters) – Trade unions protested at British ferry ports on Friday after Dubai-owned P&O Ferries abruptly sacked 800 workers via a video message, drawing widespread condemnation and raising the prospect of disruption to key tourist and goods routes. P&O, which is owned by Dubai ports firm DP World, is recovering from a difficult two years when COVID-19 prevented tourists from travelling on its routes between Britain, France, Ireland and elsewhere in northern Europe. P&O said on Thursday it had lost 100 million pounds ($131 million) in the last year and that without changes its …