Traffic Management Order
4Penalty charges for road traffic contraventions
(1)This section applies where—
(a)in relation to a GLA road or GLA side road, Transport for London or, subject to subsection (3) below, the relevant borough council; or
(b)in relation to any other road in the area of a borough council, the relevant borough council or, subject to subsection (4) below, Transport for London,
have reason to believe (whether or not on the basis of information provided by a camera or other device) that a penalty charge is payable under this section with respect to a motor vehicle
....
5)Subject to subsection (6) below, for the purposes of this section, a penalty charge is payable with respect to a motor vehicle by the owner of the vehicle if the person driving or propelling the vehicle—
(a)acts in contravention of a prescribed order; or
(b)fails to comply with an indication given by a scheduled section 36 traffic sign
..
“prescribed order” means an order under section 6 or 9 of the Act of 1984 [a Traffic Management Order] which makes provision for a relevant traffic control
The authority referred to a TMO in their reply.
In short:
TMOs make restrictions, lack of compliance with which is a 'road traffic contravention' or similar expression. However, enforcement of these is only possible under other legislation e.g. Traffic Management Act, LLA etc.