The government was right to seek a solution to the huge disruption caused by Operation Stack, but hasn't done enough to prove the viability of a £250m lorry park, a group of MPs has said.
The Transport Select Committee said that the decision to set aside £250m to build a permanent lorry park near the M20 "had left behind some of the usual best practise when spending such large sums of money" because the decision was taken "at pace".
Operation Stack is the name given to plans where stretches of the M20 are used to park freight bound for the Channel Tunnel or Port of Dover, and is implemented when a cross-Channel service is severely disrupted.
The committee of MPs found that the government's decision to proceed with the lorry park capable of holding 4,000 large goods vehicles was rushed in reaction to the events of last summer, when Operation Stack was used longer than ever before.
In fact, the lorry park would have been on a scale unprecedented in Europe, and there appears in the world to only be one lorry park on a comparable scale.
The committee said that in the evidence sessions the scale and location of the lorry park became a concern, with some witnesses stating it could cause worse disruption than was experienced during Operation Stack.
And Eurotunnel said that the lorry park would only improve the situation in the very short-term and that by the time it is built, the capacity would be too small compared to traffic growth.
"The disruption caused by Operation Stack affects many people in Kent but this is not just a local issue. The routes to Dover and Folkestone are important nationally – they carry more than 80 per cent of the road freight entering or leaving the UK," said Lousie Ellman, chair of the committee.
"The government has settled on a lorry park as the best solution but what they are proposing is on a vast scale and could cost up to a quarter of a billion pounds.
"Ministers need to do more in order to justify this spending and it should do more to demonstrate why a lorry park roughly the size of Disneyland in California is better than the alternatives we heard about during our inquiry.
"We are not saying that the government should not press ahead with its proposal, only that it has more work to do to persuade us of the business case for this investment."
A Department for Transport said: "We are acutely aware of the impact Operation Stack has on residents and businesses. It is right that we find a permanent solution and we’re determined to keep Kent moving. That is why up to £250m was made available to build a lorry park which could take lorries off the county’s roads in the event of disruption.
"Highways England received more than 1,000 responses to its public consultation on this issue and will announce a decision on the preferred site soon."
But the committee said transport ministers must carry out a cost-benefit ratio of alternatives, justify whether the scale of the park is appropriate to the frequency of disruption, assess the environmental concerns and look to local benefits.
Operation Stack was deployed on 31 days in 2015. The total number of days on which Operation Stack was used in 2015 was not unprecedented, but the number of consecutive days was unusual, the report said.