There was a time when it was possible to buy genuine wartime propaganda posters in Vietnam.

Most date from what the Vietnamese call the American War, and one example, a large diptych of two women, adorns the wall near my desk.

The serene-looking woman on the left, a porter for the Viet Cong, wears a dark shirt and carries a pack of heavy rifles on her back; it is dated 1975, the year the war ended.

On the right, a younger, more coquettish woman wears a stylish blue ao dai dress and carries a bunch of red flowers; it is dated 1995, almost a decade after the doi moi economic reforms were introduced.

The picture is called Calendar Girls, Then and Now (Beauty and Strength).

For reasons that will become clear, it is better not to reveal the artist’s name in case he might be persecuted by the authorities for his work.

That kind of thing is happening a lot in Vietnam these days, especially to artists and writers, academics and journalists, and most of all to internet users.

Many of these have set up blogs, using a nom de guerre, where they post articles and images expressing anger at the Hanoi government’s inept management of the country.

They complain that their lives are shackled, and their motto, adopted from Pink Floyd’s hit, "Another Brick in the Wall", is “We Don’t Need No Thought Control”.

It is nice to imagine sticking little quote balloons on the Beauty and Strength painting to indicate the two women are speaking these words.

If they did, they would likely be put in prison now, for the Vietnam Communist Party regime has turned on young bloggers and others who dare, even mildly, to chastise or ridicule its policies.

Across the country, hundreds of online scribes have been detained on charges of discrediting party leaders and posing a threat to national security.

Last month Phil Robertson, the deputy Asia director for Human Rights Watch, lamented the jailing of Nguyen Phuong Uyen and Dinh Nguyen Kha because they had disseminated political views.

He called it “a scathing indictment of everything that is wrong with human rights in Vietnam”.

Said Robertson: “It reveals a rights-repressing government determined to gag its own citizens and a lapdog judiciary eager to do the bidding of its political masters.”

Soon afterwards, the Communist regime went even further and passed another repressive measure called Decree 72, which bans the sharing of general information through social media.

That means internet users in Vietnam can only send personal information; they cannot quote, gather or summarise material from the press or government websites.

And they certainly cannot put quote bubbles on pictures to indicate people saying scurrilous things about Ho Chi Minh’s penchant for young ladies or the Politburo’s fondness for single malt whisky.

Metaphorically speaking, however, that pretty well sums up what the successful Communism Cafe in Hanoi has been doing – and for which it has landed in deep doodah.

Owned by a well-known singer, Linh Dung, the place is festooned with Beauty and Strength, namely vintage propaganda images, many of which have been satirically embellished.

Its menus, for example, are written on pages from Marx and Lenin, and quotes by these great men, including Ho Chi Minh, have been edited to make them appear, well, rather silly.

Now, Commies love concrete, but they hate satire. It just drives them bonkers.

So the security services are now investigating Dung’s cafe for its “blasphemous” decorations. Actually, their action is really due to the fact that it is so highly popular.

The Hanoi regime is petrified at the way Vietnam’s new tech-savvy generation holds it in almost total contempt. Hence, the launch of yet another brutal assault on free speech.

It is a morally ugly and spiritually weak move. And it is destined to fail.

The beauty and strength of the country’s young bloggers will prevail in the long run.