The Hindhead Tunnel, opened in 2011, is part of the 4-mile (6.4 km) dual-carriageway that replaced one of the last remaining stretches of single-carriageway on the A3 road which connects the cities of London and Portsmouth.

A naval dockyard has existed in Portsmouth since at least Tudor times,[4] giving significant importance to the road linking that city with London.

The original 73-mile (117 km) [5] route skirted the north-western limits of The Weald[6] climbing to the summit of Gibbet Hill close to Hindhead.

By the start of the new millennium most of the A3 had been dualled; of the route from Southfields to Havant, only the section that passed through Hindhead and the Devil's Punch Bowl was still single carriageway.

This section, which passed through an Area of Outstanding Natural Beauty (AONB), operated at or above capacity for much of the day and had an accident rate 40% higher than the national average for that class of road.

In 1983 some nine alternatives for the A3 were investigated by the Department for Transport, but assessment showed that only one which went around the north and west side of the Punch Bowl (the "Red Route"), crossing the Smallbrook Valley was viable.

[12] Most of the tunnel passes through the Upper Hythe C and D layers and the Lower Hythe A layer, which are described as "Weak, locally very weak to moderately strong, slightly clayey fine-to-medium sandstone with occasional thin beds of clayey/silty fine sand" and typically has Uniaxial Compressive Strength (UCS) values of 2–5 MPa.

The section from the car park in the London direction, which was created in 1826 to follow the Devil's Punch Bowl contour, has been returned to nature.

The higher level pre-1826 Old Portsmouth Road route across the Devil's Punch Bowl still exists, and is used a pedestrian and cycle path, and as a bridleway.

[14][15] As a result, the excavated part of the tunnel was horse-shoe in shape rather than circular, and the amount of spoil removed was 20% less than would have been the case had a TBM been used.

At the southern end, where tunneling passed through the Lower Hythe sands, the primary lining was supplemented with 4 m (13 ft) "pins" to provide more support.

[21] The opening ceremony itself, to which the public was not invited for safety reasons, was performed by the Secretary of State for Transport Philip Hammond on 29 July 2011.

[7] Electronic equipment includes linear heat detectors, radar coverage and 104 CCTV cameras that can pinpoint incidents,[19] intelligent lighting and LED cat's eyes and comprehensive fire-fighting systems.

[28] From the outset a tunnel was built rather than a cutting being dug to avoid spoiling an area of outstanding natural beauty and a Site of Special Scientific Interest, much of which is owned by the National Trust.

Common lizards, adders and slow-worms found at Boundless Valley were relocated to National Trust land at Highcombe Edge while grass snakes were taken to Hurthill Copse.

[7] Tree felling was scheduled to minimise disruption to nesting birds and to other wildlife and in certain instances, animals such as dormice were removed to similar habitats elsewhere.

It is probable that lime produced by the kilns used limestone or chalk from Petersfield 25 kilometres (16 mi) away and would have been used to counteract the acid nature of the soil.