No injuries were reported.
The man had reportedly threatened to detonate gas canisters strapped to his body, Sky News reported.
Reports said four people were taken hostage by the man, who witnesses said was shirtless when he was led away by police.
Offices along the street were evacuated after the man walked into the building with the gas canisters, The Daily Telegraph reported.
One witness told the Telegraph the man went into the offices of Advantage, a logistics company that offers instructional courses. She said he had threatened to blow himself up before taking hostages, including the company director.
Reports indicated the suspect had failed a training course three times and wanted a refund from the company.