With Brexit negotiations taking longer than expected, concerns have been raised about the readiness of Britain's borders when the country eventually leaves the European Union.

One Labour MP, who chairs the Public Accounts Committee, has warned that declarations at Britain's borders are set to skyrocket, placing huge strains on the current system in place that checks the millions of shipments made each year to the UK.

Currently, 55 million declarations are made at the UK border, but the surge of goods coming from the EU after Brexit is expected to see that figure more than quadruple to 255 million.

The committee chair, Meg Hillier said: "Failure to have a viable customs system in place before the UK's planned exit from the EU would wreak havoc for UK business, trade and our international reputation. Confidence would collapse amid the potentially catastrophic effects."

She has called on the Treasury to ensure that HM Revenue and Customs has the funds available to cope with a surge in declarations at the border.

The MP said that £7.3m would be needed to help upgrade HMRC's facilities at the border, which would be a "relatively small sum to pay to guard against the wider financial and reputational costs of failure."

Speaking to The Telegraph, a government spokesperson said: "The Customs Declaration Service is on track for delivery by January 2019 and has the capacity to deal with a significant increase in customs declarations at the border."

Hillier added that "[The Treasury] needs to progress this work urgently and obtain the additional funding required."

Brexit negotiations have been slowed by a disagreement over how much the UK should pay as part of the divorce bill.

The 'divorce' bill is what the EU says that the UK should pay as a share of money that's already been committed to various projects. There is no official bill yet decided and any amount will be a matter for negotiations.

The EU's chief negotiator Michel Barnier warned last week that Britain would need to reach a decision by the end of November or potentially see the collapse of any trade talks.

With trade talks at risk, the future of Britain's border customs with the EU could be impacted at a level unbeknownst to authorities until Brexit actually comes into place in March 2019.

Brexit speech: Immigration
File photo: UK Border control is seen in Terminal 2 at Heathrow Airport in London Neil Hall/Reuters