Long-time trade partner Bourne cited the "seismic effects" of the Covid crisis on the tourism and hospitality sectors for its decision.
A transition period is under way, with a team in place to manage any travel trade enquiries and bookings until the end of February.
Any existing trade bookings, and any additional bookings taken during the transition period, across all three Bourne brands, will be honoured.
A Bourne spokesperson confirmed agents were already being informed of the firm’s decision.
"We have had to make some difficult choices over the last few months and one of these is unfortunately the decision to exit the travel trade," said Bourne.
"This has not been an easy decision, especially as we know that our colleagues in the trade have also suffered as a result of the pandemic.
"We hugely value the relationships we have had for many years with these partners and thank them for their support.
"However, at this time we need to focus our investment in other areas of guest sales and communication."
An internal restructure at Bourne is ongoing, with new strategies and priorities for each of its brands to guide them through the pandemic "and ensure future success".
"As a result of this, we are needing to make necessary changes to the products and services that we offer," said Bourne.
"We are confident that our three brands will grow and thrive in the future, but at this stage, we cannot say when that will exactly be."
There will be organisational and operational changes at Bourne’s Hemel Hempstead support centre, and at its parks, resorts and hotels, with each of the company’s three brands operating independently of each other.