In the 1940s and 1950s, the developed area was expanding to the present site of the Westminster neighbourhood, and became part of the city with the 1961 annexation.

The non-annexed portions of Westminster Township continued to be largely rural, with the most substantial population centre being the police village of Lambeth in the west.

In the early 1990s, the City of London proposed a massive land annexation, which included the entire Westminster municipality.

[4] In 1992, after months of political debates involving the Ontario government, the City of London, and local residents, the proposed annexation was allowed to proceed.

The annexation solved infrastructure problems faced by the township subdivision of South Winds, now becoming able to be connected to city utilities without an interjurisdictional conundrum.

The area north of Highway 401 is currently represented by Lindsay Mathyssen of the New Democratic Party, first elected in 2019.

The area south of Highway 401 is currently represented by Karen Vecchio of the Conservative Party of Canada, first elected in 2015.