Vladimir Putin has spent the better part of a decade pretending Alexei Navalny doesn’t exist. The Russian president avoids calling his most prominent opponent by name, while he and state media routinely ignore the corruption allegations Mr Navalny publishes online.

But after the activist led the largest protests in Russia for years from a jail cell last weekend and published an investigation claiming oligarchs had built the president a $1.3bn palace, Mr Putin made it clear that Mr Navalny is very much on his mind.

In a rambling six-minute answer during a stage-managed meeting with students on Monday, Mr Putin admitted he had seen parts of Mr Navalny’s two-hour exposé into a lavish palace allegedly built for the president’s use on the Black Sea coast.

A day later, Mr Putin made one of his very few forays beyond his residences since the coronavirus pandemic began — to open a Moscow road junction — in an apparent response to Mr Navalny dubbing him “the old man in his bunker”.

“Look, I have not watched this [entire] film, simply because I did not have free time,” Mr Putin said when asked by a student about the Black Sea palace. “[But] nothing of what is listed there as my property belongs or ever did belong to either me or my close relatives. Never.

“This is just a convenient moment to cobble together all these materials to brainwash our citizens and put it online,” he added.

Mr Putin’s decision to address the allegations suggested concern inside the Kremlin at the attention received by Mr Navalny’s investigation, observers say. The film has racked up more than 90m views on YouTube.

His remarks came a day after Russia’s state television ran several lengthy attacks accusing Mr Navalny of being a corrupt, failed politician working on behalf of western intelligence agencies.

The attacks underscore a sense of irritation and worry in the Kremlin at Mr Navalny’s ability to harness national public anger, analysts say, while representing the latest in a series of missteps by Mr Putin’s administration in its attempts to sideline the activist.

“Why do people hit their fingers when they’re trying to hammer a nail? They should have been more careful with their hammering,” said a person who regularly speaks to Mr Putin. “The scale of the reaction increases Navalny’s importance.”

In August, Mr Navalny was poisoned with a nerve agent in an attack he and western countries claim was ordered by the Kremlin. After recovering in Germany, he returned to Russia this month, only for his flight from Berlin to Moscow to be redirected at the last minute to an airport clear of protesters, where he was arrested.

Mr Navalny was then jailed following a court hearing in a police station. He faces two separate fraud charges that could see him sentenced to a potential 13-and-a-half years behind bars.

“They’ve made a lot of mistakes in really puffing him up themselves . . . If airplanes are moved from one airport to another because of him, and hearings are moved from a court to a police station because of him, then that means he’s a really important person,” the person in regular contact with Mr Putin said.

In response, Mr Navalny called for protests across Russia last Saturday. Tens of thousands took to the streets in more than 110 cities despite strong efforts by police and federal authorities to deter them.

The scale of the rallies — where many protesters expressed anger at poor living standards as much as at Mr Navalny’s incarceration — appears to have provided the impetus for a change of approach at the Kremlin.

In an abrupt about-turn from state TV’s policy of ignoring the opposition activist’s investigations, Dmitry Kiselev, who hosts the country’s most popular news programme, devoted a nine-minute monologue this weekend to mocking Mr Navalny and praising Mr Putin, while suggesting the palace film was “produced” by Berlin and relied on documents supplied by “Nato intelligence services”.

“Navalny as a politician is an empty space . . . He never was able to organise anything,” Mr Kiselev said. Mr Putin, on the other hand, was “stable like no other politician in the world” and his modest tastes meant he had no need for such a luxurious holiday home. Later in the programme, an eight-minute segment was dedicated to corruption allegations against Mr Navalny.

“The Kremlin is absolutely sure that Navalny is working in the interests of the western intelligence services,” said Alexei Chesnakov, Mr Putin’s former deputy head of internal policy. “This is not rhetoric. It is a fact. It must be taken into consideration.”

That line of attack was redeployed on Tuesday by Nikolai Patrushev, secretary of Russia’s powerful security council, who said western countries “need [Navalny] to destabilise the situation in Russia, for social upheaval”.

Mr Navalny’s supporters have called for new rallies on Sunday, seeking a sustained protest movement to put pressure on the Kremlin. In response, Russian police have issued a slew of fines and detentions related to last Saturday’s marches and Mr Putin warned would-be protesters that “anything outside the law is not just counterproductive, but dangerous”.

“The Kremlin believes it is in control of the process . . . alertness has not morphed into anxiety. This is a nuisance, but not an emergency,” said Mr Chesnakov. “What matters is actual dynamics, not historical comparisons [to previous unrest].”