The first signs of a commuter revival in the capital appeared on Monday as London Underground recorded its busiest morning since the start of the pandemic – although schools may have played a bigger role than offices in increasing journeys.

Rush-hour trips on the tube were up 17% from last Tuesday, to just under a million – their highest since March 2020. Buses also saw 39% more passengers, according to Transport for London figures for the period to 10am on Friday.

The rise was particularly pronounced between 8am and 9am, with 22% more tube journeys and 71% more bus trips. Almost 2m contactless “tap-ins” were recorded across the capital’s two main transport modes by 10am.

Schoolchildren and parents travelling appears to have had the biggest impact, with bus journeys already rising rapidly by Friday last week, after most schools returned on Wednesday or Thursday.

However, morning tube numbers rose by 110,000, about 12.5%, from Friday to Monday, suggesting that some commuters have returned in the capital.

According to Network Rail, peak morning footfall at Cannon Street in the heart of London’s financial district for today was 8,909 passengers compared with 6,217 a fortnight ago.

A spokesperson for Canary Wharf Group, where east London’s financial district is located, said it was now busier than at any time since March 2020.

“The number of people back at Canary Wharf varies from our tenants. Some businesses have asked for everybody to return and some are asking people to return in phases. In the meantime, our shops, bars and restaurants are doing really well,” the spokesperson said.

Catherine McGuinness, policy chair at the City of London Corporation, the governing body for the capital’s square mile, said the area is “buzzing again, as the numbers on our streets grow and offices start to come back to life”.

She added: “We urge people to come back to the office and see colleagues in real life – it’s much more fun than on a screen.”

Cafes and restaurants catering for commuters said they were seeing signs of revival in city centres. Spencer Craig, the boss of the Pure cafe chain, which has 20 outlets in London, said sales in its shops were 30% up on Monday compared with a fortnight ago.

“It’s definitely busier today, although from a fairly low base. We wouldn’t expect to see the full impact for the next few days as Mondays look like they are now going to be quiet for ever, but we think that over the next couple of days it will carry on building.”

Pizza Express said trading for its restaurant group was now ahead of 2019 levels. A spokesperson said: “Across the UK the gradual return to office working is translating into slightly increased trade at our city centre sites. We are optimistic that this trend will increase further.”

Steve Grocutt at The Cornish Bakery said: “Our city centre bakeries have been slower to return to full sales … However, those locations have absolutely returned to their form … We’re in significant growth.”

Another sign of recovery in the capital came as British Airways, along with German carrier Lufthansa, restarted flights from London City airport, which mainly serves business travellers.

On the roads, traffic data from TomTom showed that morning rush-hour congestion in London peaked at 61%, almost at 2019 levels, but unchanged from last week.

Data from the West Midlands showed road traffic up from last week in the morning rush hour and approaching 2019 levels of congestion, although Manchester remained well below pre-pandemic levels.

A source from a leading rail operator said there was “no noticeable increase that we have heard about so far”. He said the industry’s “expectation is that it will be next week before we see any commuter-type increases”, despite a marketing campaign to welcome back passengers.

Leisure and weekend travel has returned faster than weekdays compared with pre-pandemic times, according to provisional Department for Transport data up to 30 August.