Prime Minister Vladimir Putin peers sanguinely down from a large billboard beside the road leading into Russia's biggest car plant, in the city of Togliatti, on the Volga.

The campaign poster depicts Putin standing coolly in sun glasses next to the AvtoVAZ factory's newest product, the Lada Granta, and says the plant is backing his bid to return to the presidency in an election on Sunday.

Never mind that this is a free and fair election where workers can vote of their own volition: Russia-Togliatti-Automotive Plant is emblazoned across the foot of the poster and huge letters beside the car declare: For!

At first glance, this might appear to defy logic.

Togliatti and hundreds of other Soviet-era cities dominated by one plant or industry are the kind of place where you might expect Putin to face hostility after 12 years in power as president or prime minister.

Most of these mono towns are in decline and epitomise the absurdity of late Soviet dictator Josef Stalin's industrialisation and urban planning.

But Putin is still more popular in Russia's provinces than in Moscow or St Petersburg, where he faces the biggest opposition since he rose to power.

Most campaign posters in the two big cities do not even show Putin's face because his standing has fallen so much there. In Togliatti, his face is everywhere.

Even critics say Putin is still popular in Togliatti, and one of the reasons is his largesse in helping bail out AvtoVAZ when it fell on hard times.

Anything is good in a famine - and that (famine) is our big problem, said Sergei Dyachkov, a retired sociologist who worked for AvtoVAZ for a quarter of a century.

The Communist party's victory over Putin's United Russia party in Togliatti in a parliamentary election on December 4 is unlikely to count against Putin because he is more popular than the party, Dyachkov said.

While there might be dislike of the party in power, there is still loyalty towards Putin, he said.

After the global financial crisis of 2008-09, the government pumped billions of dollars in interest-free or low-interest loans from state banks into AvtoVAZ, helping it survive and averting the danger of protests in Togliatti.

All those who are planning to get elected will unfortunately lose against our prime minister, said Vadim Sokolov, a former deputy mayor of Togliatti who heads a fund for the city's economic development.

He has not done (everything) - this saddens me. But he's trying, he's doing a lot of work. He is reliable.

SOVIET HERITAGE

Togliatti, a city of 720,000, lies on the banks of the Volga River about 1,000 km (600 miles) southeast of Moscow. Named after late Italian Communist leader Palmiro Togliatti, it is one of the largest of the mono cities from the Soviet era.

The Soviet Union's central planning built most of them far from Moscow and St Petersburg, often with poor infrastructure and no means of surviving if the economy falters.

Vladimir Gusev, chief executive of a major engineering company who loves living in Togliatti, says the whole concept of mono cities was wrong.

Mono towns - this is a road to nowhere, Gusev said. If AvtoVAZ has economic and salary problems, that means the city has problems.

The fatal flaws became obvious during the 2008-09 crisis, particularly when a strike broke out Pikalyovo, a mono town of 22,000 in northern Russia.

Almost entirely dependent on a cement-producing complex owned by one of Russia's richest men, Oleg Deripaska, workers revolted when plants were shut down, leaving thousands out of work and a huge backlog of unpaid wages.

Putin went to Pikalyovo and theatrically threw a pen at Deripaska, ordering him to pay the workers and get them back to work. Such tactics could now pay dividends for him.

Putin has played an effective card (in Togliatti) and in other mono towns, Dyachkov said.

There have been two opposition protests in Togliatti since the December 4 parliamentary election but they were small because local people are convinced their lives will not change, organisers said.

What is most painful to me is that people are complying with all of this, are resigned to their fate, said Pyotr Zolotaryov, an independent trade union leader. But there is one reason for that. People are worried about losing their job.

That fear is palpable in Togliatti's makeshift beer bars made of wood and covered only with an aluminium siding, where workers gather after work.

At one of them, called the Office Bar, which serves a cheap beer named after the Zhiguli car produced by AvtoVAZ, a 27-year-old worker at the plant moaned about the lack of alternative work as he had a drink after his day's shift.

I have a job and I don't want to lose it, said the worker, who gave his name only as Anton. Do I like it? Hell, no, but what is my alternative if I have to feed a wife and two kids?

Zolotaryov said some workers would also vote for Putin simply because of traditional blind faith in their leaders.

It is not because Putin has done anything special for them, he said. It's just lack of political awareness ... People don't stop to think why things are going the way they're going.

WHAT DOES THE FUTURE HOLD?

AvtoVAZ, which is majority-owned by the state, has at least survived the economic crisis and posted a net profit of around 3.6 billion roubles (77.3 million pounds) last year.

Initially known as VAZ and established in Togliatti in the 1960s, it says its plants, services and suppliers affect 4 million people's finances.

Unemployment is relatively low, about a quarter of the national figure of 6.6 percent. But pay is miserable and wage arrears in the Samara region, where Togliatti is located, grew last year by 30 percent - while it fell in Russia as a whole.

AvtoVAZ pays its workers on time but has cut its labour force to 66,000 from 104,000 in the past three years, partly due to restructuring, the impact of which has been felt on the whole city, critics say.

That's when the city's degradation really started, Dyachkov said. The degradation went everywhere - in business, finances, professional and human relations - and that's the story. It's not a mono town, it's a depressing town.

Mayor Anatoly Pushkov, who is about to leave office, said the city's biggest challenge now was to attract investment.

For Togliatti to grow, it needs more funds, Pushkov said.

That is not an easy problem to resolve. There are no specific funds in the state budget for mono cities. Any funding for them has mostly come out of anti-crisis funds.

Official figures show there are 335 single-industry towns in Russia, half of them with fewer than 20,000 inhabitants. Industry experts say the total is higher, around 800 towns and settlements, and the economic impact affects millions of people.

The Union of Russian Cities, a government group, said in a report that 35 of the mono towns were in an economically disastrous state in 2010.

It is estimated that more than 1 trillion roubles ($34.45 billion) would be needed by 2020 to modernise the towns, mainly to finance construction projects and revamp infrastructure.

This year will not be easy at AvtoVAZ. The Association of European Businesses says auto sales in Russia are expected to grow by a modest 12 percent this year to 2.8 million units - a sharp drop from the 39 percent growth of last year.

January data showed AvtoVAZ's sales were down 21 percent year-on-year.

But France's Renault is expected to raise its holding to a controlling stake and there are plans to produce new Renault and Nissan vehicles.

The 1.5-km (one-mile) long production lines at AvtoVAZ are being revamped to increase efficiency after sales last year of 634,000 vehicles, and the Lada Granta has gone into production this year with a starting price of 229,000 roubles.

AvtoVAZ is determined to make this year profitable.

We don't have any other option, said AvtoVAZ spokesman Alexander Shmygov.

Dyachkov said the government would not risk letting such a large city end up in ruin. You cannot joke with such a city like Togliatti, he said. That's why the government, one way or another, will feed it. But not other mono-towns.

($1 = 29.0313 Russian roubles)

(Additional reporting by Gleb Stolyarov and Alissa de Carbonnel; Writing by Lidia Kelly; Editing by Timothy Heritage/Maria Golovnina)