Tankonomics: How much do they cost to supply and support?

From the BBC World Service: A deal has finally been done to send American and German tanks to Ukraine. President Volodymyr Zelensky says they need to be delivered quickly, but just how realistic is that - and how costly? We hear from the former commander of the British Army's tank regiment. Millions of Pakistanis were left without power this week after a major failure of the country's energy grid. The system is back up and running but businesses tell us they fear more cuts, and the disruption they bring. And, how the Dutch have made more space for cyclists by building an underwater bike park.