Demand response (DR) services have the potential to enable large penetration of renewable energy by adjusting load consumption, thus providing balancing support to the grid. The success of such load flexibility provided by industry, communities or prosumers and its integration in electricity markets, will depend on a redesign and adaptation of the current interactions between participants. There are three models upon which a DR services can be provided: i) the electricity consumer provides flexibility through an aggregator; ii) the electricity consumer provides flexibility directly to the market; iii) an aggregator enables flexibility to another aggregator. New challenges however, are bound to appear with large scale of smaller assets contributing with its flexibility. Among others are the dispatch coordination, the validation of delivery of the DR provision, the corresponding settlement of contracts and assuring secured data access among interested parties. In this study we apply distributed ledger (DLT)/blockchain technology to securely track DR provision through an aggregator, assuring data integrity, origin, fast registry and sharing within a permissioned system, among all relevant parties (including TSO, Aggregators, DSOs, balance responsible parties (BRP) and prosumers). Moreover, as a proof of concept, the DR service is deployed on Hyperledger Fabric framework in a laboratory emulated IT environment in order to study its feasibility. The use case results are presented after a lab implementation and simulation work, which includes a 450 kW energy storage system scheduled to provide DR services to the grid, upon a system operator request and the corresponding validations and verifications are done, followed by the publication on a distributed ledger. Results and performance metrics such as transaction round trip time, latency and memory usage are presented and discussed as a solution for large scale implementation, considering different number of blockchain participants and transaction per second. The performance of the implementation, show scalable results, which enable real world adoption in supporting the development of flexibility markets with the advantages of blockchain technology.