Ms Jackson's partner Stephen Sinnott, 38, said: "Because the barriers were still down we had to queue inside the tunnel for about 10 minutes before we even got outside.
It was total madness." Barriers on the toll booths were not raised immediately because staff were helping to divert traffic out of the tunnel to safety, which was closed in both directions until 6.30pm while traffic was diverted to the Kingsway (Wallasey) Tunnel.
Emergency services were on the scene within two minutes. A spokeswoman for Merseyside Fire Service said: "We had four pumps on scene to put out the fire caused by a wiring fault in the Citroen. The tunnel was evacuated and ventilated."
A series of safety measures, costing £7m, have been introduced in the Mersey Tunnels to bring them up to 21st century standard. They include three new escape tunnels, more escape passages and underground bunkers which can hold up to 980 people.
Last night a Merseytravel spokesman praised the way the emergency services had dealt with the blaze.
Drivers were urged to contact the organisation for a refund if they paid the toll and their claims will be checked against CCTV footage of cars at the booths.