Jeremy Corbyn got straight back to campaigning on Thursday after his holiday, touring Cornwall for a visit and rally focusing on what he said was Theresa May’s poor record on the NHS.

The Labour leader, newly returned from a break in Croatia, visited the Royal Cornwall hospital in Truro before addressing a crowd of supporters at Heartlands, a tourist attraction near Redruth.

Corbyn has said Labour will be in “permanent campaign mode” and is planning a succession of visits and events, many taking in Conservative-held seats across England and Wales and SNP ones in Scotland.

Speaking after his visit to the hospital, where he stopped to pose for pictures with staff, patients and families, Corbyn said the NHS was “going from bad to worse” under the Conservatives.

“The times to see a doctor are increasing, the times to be treated in A&E departments are increasing, the times to get elective surgery are increasing. We can’t go on like this,” he told Sky News.

“The NHS is something we all rely on. It’s up to government to make sure it’s there for everybody all the time.”

Jeremy Corbyn gives a speech in Redruth. Photograph: Matt Cardy/Getty Images

He said the health service was being hampered by cuts and understaffing. “Labour would, firstly, properly fund our NHS by putting emergency money in. Secondly we’d lift the pay cap to ensure there are sufficient staff at the NHS to stay there and do the work, and thirdly invest urgently in reinstating the nurse bursary so that we have a good number of nurses for the future.”

To coincide with Corbyn’s visit, Labour publicised NHS statistics it said showed that in the year since May became prime minister, more than 2.5 million people had waited more than four hours to be seen at an A&E department, and 280,000 more people were on treatment waiting lists.

Corbyn was to spend Friday on visits to Bristol and Swindon, with the day’s focus on what Labour says is a decline in statistics for cancer treatment under the Conservatives.

More than 105,000 people waited more than two weeks for an initial consultant appointment during May’s first year, more than double the number five years ago, Labour said its statistics showed.

Corbyn’s schedule is tailored around marginal seats that Labour would hope to gain if it is to win a majority.

On Thursday he took in the seats of Truro and Falmouth and Camborne and Redruth, both of which saw their Tory majorities greatly reduced in the June election. His travels on Friday will take him into areas similarly held by Conservative MPs with ebbing margins of victory.