Labour's Employment Rights Bill promises workers flexible working, is supposed to protect them from unfair dismissal from day one of their new job, and make it easier for them to go on strike. In particular, according to Louise Haigh this week, it will stop companies doing what ferry operator P&O did two years ago and fire UK staff so that it could hire overseas agency staff at a lower rate of pay.

'In less than 100 days of this government,' Haigh told ITV this week, 'we have brought forward legislation that will mean P&O Ferries and the scandal that it brought to Britain will never happen again.'

The Employment Rights Bill contains a measure which seems to be specifically aimed at P&O: it demands that workers employed on boats which call at UK ports more than 120 times a year are employed on terms which conform to UK employment law.

But there might just be a catch: enhanced employment law might mean that it is harder to land a job in the first place. As the government is discovering, there is a price to pay for tighter employment laws - and in particular for attacking companies which are creating jobs. Two days after Haigh dug her stilettos into P&O, its parent company, DP World, suspended its project to expand docks at London Gateway container port on the Essex bank of the Thames Estuary - which would have created several hundred jobs.

You don't have to defend P&O's employment practices - which were also criticised by the previous government in 2022 - to appreciate that it pays to be a little more subtle when you are trying to impose new legislation on employers. The government might just have managed to get away with the Employment Rights Bill - DP World was due to announce the expansion of London Gateway at Labour's International Investment Summit in London next week - had it not been for Haigh's all-out attack on the company. She went on to describe P&O as a 'rogue operator' and said she had been boycotting their ferries for the past two and a half years, adding, 'I encourage consumers to do the same.'

Should it really be a surprise that DP World is now going to boycott her? Surely, as Transport Secretary, she knew that the announcement of London Gateway's expansion was coming up. How did she think the company was going to react at being treated as a pariah a few days before appearing at a government summit?

It speaks of a somewhat poor understanding of human nature on Haigh's part. She wouldn't, I imagine, expect to make much headway in negotiations with a trade union if she had just lambasted its leaders in public. In any case, P&O has since switched back to employing local staff on its cross-Channel ferries rather than overseas agency workers. But for some reason, Haigh - and not she alone among government ministers - seems to think that business leaders can be treated as punchbags: that you can damn them as evil capitalists and yet still expect them to line up to help you out by investing in the UK.

Keir Starmer has said on a number of occasions that he has taken Labour from a party of protest to a party of government. It seems as if the message has failed to get through to Louise Haigh.