Harrow has awarded a contract to supply and maintain its vehicles and equipment to Go Plant Fleet Services
This includes an initial eight-year deal worth a total of more than £25 million.
The full-service agreement, which includes fleet management services, will also incorporate the authority's substantial workshop and the TUPE transfer of 10 existing maintenance staff.
Up to three additional jobs will also be created by the move, which went live on January 1.
Go Plant Fleet Services will provide full contract hire with maintenance for around 140 brand new assets including compact sweepers, 7.5 and 12-tonne refuse collection vehicles and 60 accessible buses.
The deal includes grounds maintenance equipment such as tractors, mowers and rollers as well as quad bikes for weed spraying activity.
The company will additionally provide a 'maintenance only' service for the remainder of the authority's 350-strong fleet, which also features RCVs, road sweepers and various light commercial vehicles.
A seamless transition of service delivery means residents will be entirely unaffected by the authority's decision to switch providers.
Cllr Varsha Parmar, cabinet member for Environment at Harrow Council, said: 'This important decision forms a key part of the authority's overall environment strategy.
'We want to continue to collect all bins on time and sweep all streets and grounds regularly while delivering the best possible provision to the public. That means having vehicles that meet the service requirements whilst also being cost-effective.
'We chose Go Plant Fleet Services for its vast experience and expertise.
â€œThe company will supply and maintain our fleet and we're fully confident it will deliver value for money and meet our requirements'
The contract is the largest in the 40-year history of Go Plant Fleet Services, which now operates 44 depots and service centres across the UK.
Commercial Director Mark Gallimore said: 'It's a substantial deal for us and it will have a hugely positive impact on the business.
'We are in a period of nationwide expansion and this will help us to build on the outstanding progress we've made in the last 12 months.
'It will provide the perfect platform for further growth, particularly in the London area, and is a major step towards our goal of developing the business on every level'
The operation will remain based at the authority's own workshop, at Forward Drive in Harrow, which itself is being rebuilt. Work to build a custom amenity, including an Authorised Test Facility along with a full body and paint shop, is already underway and is expected to be completed by November 2019.
Delivery of the new vehicles, sourced from various manufacturers and suppliers, began before Christmas and will continue on a phased basis during the first half of 2019, with the delivery of RCVs supported by the company's own spot hire fleet.
Go Plant Fleet Services has contracts with more than 60 local authorities across the UK as part of its fast-growing nationwide operation.
'And it's that kind of experience and expertise that helped secure the contract with London Borough of Harrow,' said Mark Gallimore.
He added: 'We're a company with a vast depth of knowledge and experience in this sector so we have the capability, capacity and infrastructure across every level of the business to deliver quality and value on major contracts like this.
'Safety, compliance and sustainability were factors very much at the heart of the deal and there are a significant number of Key Performance Indicators to meet during the life of the contract.
'But we operate to the highest industry standards and we've made sure this entire operation will conform to that approach from day one.
'We have also made a commitment to provide added corporate social value including the delivery of apprenticeships within the borough and complimentary road sweepers to carry out clean-up operations after events'
The scope of the eight-year partnership, which includes an option to extend, might be expanded with future proposals to make the workshop operation available to third-party customers.