Unanswered questions about the viability of the St Albans rail freight scheme has fuelled fears about further collateral pollution if it becomes a lorry depot.

If a Strategic Rail Freight Interchange (SRFI) cannot go ahead, due to infrastructure and timetabling concerns, the plans could transform into a depot - meaning more lorries onto the road than already proposed.

St Albans MP Anne Main has asked for an urgent meeting with the Transport Secretary over the plans, and independent campaigner Andrew Love has urged residents to be aware of the “hidden killer” - air pollution.

He says the M25, M1, A1(M), A5 and A414 are already too congested, linking harmful emission to premature death.

Andrew called on politicians from across the district, including district council leader Julian Daly and Harpenden MP Peter Lilley, to fight the scheme: “We need you all to unite as our elected representatives and protect your constituents, young, old and middle age - from the hidden killer called ‘air pollution’.

“Please don’t just leave it to Robert Gordon, Anne Main, and Oliver Dowden to fight this monstrous SRFI development.”

The planned Park Street SRFI was given outline planning permission in 2014 as long as the developers, Helioslough, adhered to conditions such as creating a new country park and a relief road in the surrounding area.

St Albans district council (SADC) originally refused planning permission, but in 2009 it was approved on appeal by former communities secretary Eric Pickles.

SADC fought this decision, taking their case to both the High Court and appeals court, but permission was upheld both times.

In a letter to Transport Secretary Chris Grayling, Mrs Main said plans may not be commercially or operationally feasible: “For many years now I have been implacably opposed to this development - not least because I have never had any substantive answers about SRFI’s viability.”

She said she has been pushing Network Rail to answer her questions, but they have been unresponsive - calling assurances “vague and unrealistic”.

Mrs Main noted that commuters in St Albans “pay some of the highest rail fares per yard in the country, and since the works at London Bridge have had to endure an often extremely disrupted service”.

She added: “I believe this is likely that SRFI will eventually function simply as a lorry depot, putting further strain on the roads around St Albans, particularly the A414.

“This will mean we have lost the Green Belt, not for something that the people of St Albans want or need, but for something that will be entirely different than that which overcame the very significant planning requirements and constraints.”

She said Hertsmere MP Oliver Dowden shares her concerns.