More than 60 police officers turned out at the chemical plant at Saltend yesterday to limit the scale of the disruption seen on Monday when traffic was brought to a halt on the A63 by protesters standing in the road.

The Yorkshire Post said there were two arrests, one under the Public Order Act and the other for obstructing a highway.

The unofficial protest is now in its fifth week and started when 400 workers who were working for Redhall Engineering on the BP-led Vivergo consortium biofuels project were laid off.

Police said public support for the workers appears to be waning, with drivers angry at repeated delays near the plant and unhappy by a new tactic adopted by protesters yesterday which saw them walking backwards and forwards on pelican crossings to stop traffic on the main road.

Chief Inspector Darren Downs said the protests had been generally peaceful but there had been several days, including Monday, where protesters “had caused serious disruption and put people in serious danger”.

He said unions had reneged on an agreement with police to conduct their protest in a peaceful manner.

Downs said officers would now enforce the Public Order Act, which set limits on the numbers of those who could protest and the times when they demonstrated, to avoid a repeat of the earlier scenes.

He said a stand-off ensued after demonstrators were told of the change in tactic, resulted in a “bit of scuffling, pushing and shoving” and two arrests.

Downs told the Post: “I think public support is waning because they have overstepped the mark and they are affecting the community and it has been going on the length of time it has.”

GMB official Les Dobbs said the police presence was “excessive”. He said the 48-hour suspension would let talks go ahead with Vivergo and if that didn’t happen they woul d be back at the gates.

He added: “I wouldn’t condone traffic being stopped; it is not going to help our cause or their cause. I am not going to say members are wrong. You have to look at where they are coming from, losing five weeks of pay. If you put yourself in their position they are frustrated at not being able to pay their bills.”

A Vivergo spokeswoman said: “Despite some reports to the contrary, the Redhall workers affected by the termination hold no legal right to TUPE transfer to Vivergo Fuels. Vivergo is a fuel company and therefore wouldn’t be able or have any reason to employ 300 plus engineering workers directly.

“We have stressed to the unions concerned that when the new contractors are in place any new employment opportunities will be advertised so that former Redhall workers can apply for the resulting jobs.

“In order to bring new contractors in to complete the construction and in turn promote any new employment opportunities, it is imperative that access to our site is not prohibited or impacted by protest activity.”