The lorry carrying the steam engine is thought to have started its journey in Suffolk
Twenty-three people were hurt, seven seriously, when a bus crashed with a lorry carrying a steam engine.
The crash happened on East Road, East Mersea, Essex, just before 09:50 BST.
The bus driver, a 44-year-old man from Colchester, was freed by firefighters and airlifted to Royal London Hospital with life-threatening injuries. Six passengers were seriously injured.
A man, 51, from Great Yarmouth, was held on suspicion of causing serious injury by dangerous driving.
The road is likely to remain closed for most of the day, Essex Police said.
Twenty-three people were hurt in the crash
Police said there were 35 people, including the driver, on the number 67 bus when it crashed.
Of these, 16 had minor injuries or were walking wounded.
The six passengers with serious injuries were taken to the Colchester General or Broomfield Hospital.
Officers believe the lorry had travelled from Lowestoft, Suffolk, on Wednesday morning and have appealed for information.
