Although the Piccadilly Circus to City of London branch proposal of 1905 was never revisited after its withdrawal, the early plan to extend the branch south to Waterloo was revived a number of times during the station's life.
The extension was considered in 1919 and 1948, but no progress towards constructing the link was made.

In the years after the Second World War, a series of preliminary plans for relieving congestion on the London Underground had considered various east-west routes through the Aldwych area, although other priorities meant that these were never proceeded with.
In March 1965, a British Rail and London Transport joint planning committee published "A Railway Plan for London", which proposed a new tube railway, the Fleet line (later renamed the Jubilee line), to join the Bakerloo line at Baker Street then run via Aldwych and into the City of London before heading into south-east London.
An interchange was proposed at Aldwych and a second recommendation of the report was the revival of the link from Aldwych to Waterloo.
London Transport had already sought parliamentary approval to construct tunnels from Aldwych to Waterloo in November 1964, and in August 1965, parliamentary powers were granted.
Detailed planning took place, although public spending cuts led to postponement of the scheme in 1967 before tenders were invited.
By 1979, the cost was estimated as £325 million, a six-fold increase from the £51 million estimated in 1970.
A further review of alternatives for the Jubilee line was carried out in 1980, which led to a change of priorities and the postponement of any further effort on the line.
When the extension was eventually constructed in the late 1990s it took a different route, south of the River Thames via Westminster, Waterloo and London Bridge to provide a rapid link to Canary Wharf, leaving the tunnels between Green Park and Aldwych redundant.

With the Aldwych branch receiving no extensions, it remained a lightly used shuttle service from Holborn.
The branch was considered for closure numerous times, but it survived.
Saturday services were fully withdrawn on 5 August 1962.
Maintenance costs of the station and aged lifts were high at over £3 million, which failed to meet safety standards at the time.
In August 1993, a public inquiry was held for closure of the short branch line.
On 30 September 1994, the branch was closed to traffic.
The disused station is now used for commercial filming and a training facility.

On 18 November 1987, a massive fire broke out at King's Cross St. Pancras, where the incident was near the Northern / Piccadilly line escalators which killed 31 people.
As a result, wooden escalators were replaced at all Underground stations.
The Piccadilly line platforms remained opened, but with the escalators to the ticket hall closed for repairs.
Access was temporarily via the Victoria line or Midland City platforms.
New escalators were fully installed on 27 February 1989.

On 7 July 2005, a Piccadilly line train was attacked by suicide bomber Germaine Lindsay.
The blast occurred at 08:50 BST while the train was between King's Cross St. Pancras and Russell Square.
It was part of a co-ordinated Islamist terrorist attack on London's transport network, and was synchronised with three other attacks: two on the Circle line and one on a bus at Tavistock Square.
The Piccadilly line bomb resulted in the largest number of fatalities, with 26 people reported killed.
Owing to it being a deep-level line, evacuation of station users and access for the emergency services proved difficult.
Shuttle services had to be introduced between Hyde Park Corner and Heathrow loop, between Acton Town and Rayners Lane, and between Arnos Grove and Cockfosters.
Full service was restored on 4 August, four weeks after the bomb.

On 15 December 2006, a birthday card was revealed by Tim O'Toole, then London Underground Managing Director during a 100-year celebration of the Piccadilly line at Leicester Square station.
Although the Piccadilly Circus to City of London branch proposal of 1905 was never revisited after its withdrawal, the early plan to extend the branch south to Waterloo was revived a number of times during the station's life. The extension was considered in 1919 and 1948, but no progress towards constructing the link was made.
In the years after the Second World War, a series of preliminary plans for relieving congestion on the London Underground had considered various east-west routes through the Aldwych area, although other priorities meant that these were never proceeded with. In March 1965, a British Rail and London Transport joint planning committee published "A Railway Plan for London", which proposed a new tube railway, the Fleet line (later renamed the Jubilee line), to join the Bakerloo line at Baker Street then run via Aldwych and into the City of London before heading into south-east London. An interchange was proposed at Aldwych and a second recommendation of the report was the revival of the link from Aldwych to Waterloo. London Transport had already sought parliamentary approval to construct tunnels from Aldwych to Waterloo in November 1964, and in August 1965, parliamentary powers were granted. Detailed planning took place, although public spending cuts led to postponement of the scheme in 1967 before tenders were invited. By 1979, the cost was estimated as £325 million, a six-fold increase from the £51 million estimated in 1970. A further review of alternatives for the Jubilee line was carried out in 1980, which led to a change of priorities and the postponement of any further effort on the line. When the extension was eventually constructed in the late 1990s it took a different route, south of the River Thames via Westminster, Waterloo and London Bridge to provide a rapid link to Canary Wharf, leaving the tunnels between Green Park and Aldwych redundant.
With the Aldwych branch receiving no extensions, it remained a lightly used shuttle service from Holborn. The branch was considered for closure numerous times, but it survived. Saturday services were fully withdrawn on 5 August 1962. Maintenance costs of the station and aged lifts were high at over £3 million, which failed to meet safety standards at the time. In August 1993, a public inquiry was held for closure of the short branch line. On 30 September 1994, the branch was closed to traffic. The disused station is now used for commercial filming and a training facility.
On 18 November 1987, a massive fire broke out at King's Cross St. Pancras, where the incident was near the Northern / Piccadilly line escalators which killed 31 people. As a result, wooden escalators were replaced at all Underground stations. The Piccadilly line platforms remained opened, but with the escalators to the ticket hall closed for repairs. Access was temporarily via the Victoria line or Midland City platforms. New escalators were fully installed on 27 February 1989.
On 7 July 2005, a Piccadilly line train was attacked by suicide bomber Germaine Lindsay. The blast occurred at 08:50 BST while the train was between King's Cross St. Pancras and Russell Square. It was part of a co-ordinated Islamist terrorist attack on London's transport network, and was synchronised with three other attacks: two on the Circle line and one on a bus at Tavistock Square. The Piccadilly line bomb resulted in the largest number of fatalities, with 26 people reported killed. Owing to it being a deep-level line, evacuation of station users and access for the emergency services proved difficult. Shuttle services had to be introduced between Hyde Park Corner and Heathrow loop, between Acton Town and Rayners Lane, and between Arnos Grove and Cockfosters. Full service was restored on 4 August, four weeks after the bomb.
On 15 December 2006, a birthday card was revealed by Tim O'Toole, then London Underground Managing Director during a 100-year celebration of the Piccadilly line at Leicester Square station.
Piccadilly line