Route 724 was included in the sale of London Country North West to a management buyout when privatised in January 1988, in turn passing to Luton & District Transport in 1990, British Bus in 1994 and finally the Cowie Group in August 1996.

These were the result of a Quality Bus Partnership between Arriva Shires & Essex, BAA and Hertfordshire County Council.

[11] In February 2021, the Citaros were replaced by a fleet of 8 Alexander Dennis Enviro200 MMCs, which were transferred from Arriva Kent Thameside.

[12] In July 2022, part of the batch of ADL Enviro200 MMCs were replaced by Wright Pulsar 2 bodied VDL SB200s transferred from Leicester in return for the Enviro200s.

From 24 July 2022, additional early morning, late evening and weekend journeys were introduced in conjunction with the Heathrow Airport Partnership.