In 1927 work began on improving the approaches on both sides of the river, including the removal of some old wharves on the Westminster shore.The southern approach was to be about 80 feet further upstream, so that the new bridge did not pass too close to Lambeth Palace.

In 1929 a temporary footbridge was built and in June work on the demolition of Barlow's bridge at last began. The new bridge was designed by Sir George Humphreys, the LCC engineer, with G.Topham Forrest and Sir Reginald Blomfield acting as architectural consultants. The original estimate for the scheme had been £638,000, but the final cost, including the approaches, was nearly £1 million.

The bridge is of five segmental steel arches, and the piers and abutments are clad in Cornish granite.The central span is 165 feet wide, the next two 149 feet, and the shore spans are 125 feet.

The bridge is 60 feet wide, with a roadway of 36 feet and two footpaths 12 feet wide. The balustrade is of cast iron, and sitting on it between the piers are two unusual cast-iron lattice-work lamps. Above each pier are the carved LCC coats of arms, flanked by dolphins, and above them are Art Deco lamp standards in the form of obelisks, mirroring the pairs of larger obelisks at each end of the bridge. These four obelisks are the most prominent element of the bridge; they are topped with what are often referred to as pineapples and are said to commemorate the Tradescants, the royal gardeners who lived in Lambeth and are said to have introduced the pineapple to Britain. When the bridge was opened, these 'pineapples' became the subject of much debate, and the local newspaper, the South London Press, made some enquiries. Neither of the bridge's architects would comment, but Topham Forrest's secretary said: 'So far as is known they are just decorations. I don't know if the form is traditional, but it is certainly not original. 'The 'pineapples' look much more like pine cones, which have been used since ancient times as a decorative motif but are also a symbol of welcome or good luck.






The temporary bridge was taken down in May 1932, and pedestrians were allowed to use one of the footpaths before the bridge was officially opened by George V, accompanied by Queen Mary, on 19 July. A pavilion for more than a thousand guests was set up on the new roundabout at the Westminster end of the bridge, and other guests were entertained on boats moored alongside the bridge. After the usual speeches, the King opened the bridge by pushing a switch that opened the temporary barriers. The King and Queen then drove across the bridge, which was lined on both sides by schoolchildren from both Lambeth and Westminster. Huge crowds had come to watch the opening and after the ceremony the bridge was filled with people wanting to be among the first to cross it.
Rather like Southwark Bridge, Lambeth Bridge has never been one of London's busiest, as it is not on a major through route. Trams never crossed it, and the tramline crossing its southern end was seen by some as an impediment to vehicular traffic. The present roundabout on the Lambeth side was not created until the 1940s.

The bridge is painted mostly in red, which is the colour of the seats in the House of Lords, whose chamber is at this end of the Houses of Parliament. Similarly, the predominant colour on Westminster Bridge is green, the colour of the seating in the House of Commons. Lambeth Bridge offers one of the finest views of the Houses of Parliament and Westminster Bridge, with the medieval gatehouse of Lambeth Palace on the right. Looking upstream, the view is more modern, with the glass Millbank Tower on the right and a huddle of contemporary buildings at the southern end of Vauxhall Bridge. On the north bank, on the left-hand corner of Horseferry Road, is Thames House, built at the same time as the bridge, which now houses MI5, the country's domestic secret service organisation.