Newspaper headlines: 'Final countdown' in referendum campaign

The latest in the EU referendum campaign, migrant smuggling by sea, health issues and a cricket milestone make the front pages.

The Guardian says that with 23 days until the referendum "politics is only going to get stranger".

The paper adds that Prime Minister David Cameron plans to step up campaigning as he battles to stop the debate sliding into an argument about his leadership of the Conservative Party.

"David Cameron's battle to keep Britain in the European Union enters its final phase today," states the Guardian.

Meanwhile, the paper says the Brexit camp will move its own campaign up a gear this week as Boris Johnson and Michael Gove appear together for the first time on a tour of the north of England.

The Guardian continues: "Yesterday, the prime minister praised Sadiq Khan, the newly elected mayor of London, just weeks after claiming the mayor was unfit for office because of links to Islamist extremists.

"However, Cameron's attempts to decouple the referendum from his own party and leadership will be difficult, given that it is inevitably being seen as the biggest gamble of his career, which will decide his future in Downing Street as well as the direction of the country."

The i says the campaign to keep the UK in the EU is "desperately seeking a united front" as Mr Cameron and Mr Khan "put aside their differences".

The Mail remarks: "What a difference a few weeks makes in the fickle world of politics."

Save our meadows from mediocrity: Attempts to bring the colour back to the English countryside are being jeopardised by generic wildflower mixes sold by most seed companies, according to a leading nature charity Times

How a cup of tea could help to construct colonies on Mars: Researchers have found a way to modify a bacteria found in kombucha, a type of fermented tea, which means astronauts could develop the material to start building components for colonies on other planets from just a few microbes Telegraph

Kubrick's plans included new Pinocchio film: Stanley Kubrick was planning his first children's film and his first World War Two movie shortly before his death in 1999, his friend and former assistant has revealed Guardian

Is it coming home? Football kicked by Tommies at the Somme put up for sale by French owner: A French collector may be ready to part with a football kicked by troops to spur their advance to the German lines at the Battle of the Somme Mail

The papers express concern about Britain's borders after migrants were rescued in the English Channel at the weekend.

The Times reports that the Home Office dismissed concerns by the independent chief inspector of borders and immigration about the smuggling of people in small boats as "not significant" only months ago.

The paper says the Channel incident prompted fears that tighter security at bigger ports was forcing people traffickers to bring migrants across the Channel in small boats and landing at isolated harbours.

There were warnings in Norfolk and Suffolk that remote creeks and estuaries were attractive to smugglers because there were few patrols, it adds.

The Mail claims there have been four reports - the most recent last week - warning ministers that Britain's small ports are an easy target for people smugglers.

"As evidence grew of smugglers repeatedly targeting small harbours, there are fears Britain's soft underbelly has been left exposed," it says.

The Telegraph says immigration union leaders warned that Britain faced its biggest onslaught of people smugglers.

The Guardian states: "The incident has sparked concern that the UK may be seeing the start of a new trend of people being smuggled across the Channel, with some questioning whether the resources available to the Border Force are sufficient for it to police the borders."

In a leading article, the Times says the official response has so far been tardy, complacent and ineffective.

"The numbers drowning each week and the catastrophe unfolding across the Mediterranean have diverted attention and fostered complacency," it says.

"Only a few months ago the Home Office assessed the risk of migrants landing in Dorset or Dymchurch instead of Italy and Greece as 'not significant'. The Channel has proved it wrong."

The Telegraph believes the government must do more to protect the UK's borders.

It comments: "Even with the additional resources that will be given to maritime patrols, in the form of a string of new vessels and three new maritime co-ordination hubs, the Border Force's ability to patrol the seas around Britain will be limited at best.

"And giving all staff appropriate powers to board all vessels will mean little if those staff are too scarce to scrutinise the ships that could bring illegal immigrants.

"So we must point out that still more has to be done. The need for even greater action is being very visibly demonstrated in the English Channel this week, as would-be migrants attempt clandestine crossings, often at risk to their own lives."

The Mail asks how much more evidence the government needs that Britain's border security is a "shambles" before deciding to do something about it.

And the Express wonders what the point of increasing port and airport checks is if the country's coast is left undefended.

The Express leads with research that suggests reducing weight by 10% cuts the risk of developing type 2 diabetes by 90% in those most susceptible to the condition.

Health experts say this can be safely achieved by following a strict calorie-controlled crash diet programme - or eat soup to slash your risk, as the Express puts it.

Meanwhile, the Times also has a story about diabetes.

The paper reports that a pilot study of a low-carbohydrate diet to treat type 2 diabetes, involving 80,000 people, has shown that it may successfully control the condition.

The Times continues: "By rejecting guidelines and eating a diet low in starchy foods but high in protein and 'good' saturated fats, such as olive oil and nuts, more than 80% of the patients said that they had lost weight."

The Mirror highlights a skin cancer breakthrough in which a patient was given a mix of two immunotherapies that made his tumours disappear.

The paper says one expert said doctors could start talking seriously about a "cure" for cancer.

The Mirror comments: "More than 2,000 Britons die every year from melanoma, with cases on the increase thanks to greater UV exposure and the sun bed craze.

"So today's revelation from the Fred Hutchinson Research Centre will cheer families affected by this cruel disease."

Several front pages picture England cricket captain Alastair Cook after he became the youngest player in Test history to score 10,000 runs.

Times chief cricket correspondent Mike Atherton writes: "Ten years ago, two young cricketers travelled from the Caribbean together, called up from an England A tour for the main event in India.

"Their names were James Anderson and Alastair Cook, the latter barely known then and uncapped, but who yesterday became the first England batsman to pass 10,000 Test runs."

Telegraph cricket news correspondent Nick Hoult describes how Cook started the series needing 36 to reach 10,000 runs but made 16 at Headingley, 15 in the first innings at the Riverside and looked set to have wait until Lord's next week until Sri Lanka scored enough runs to make England bat again.

Vic Marks in the Guardian writes: "Here he was under the leaden skies of the north-east in front of a few thousand sturdy stalwarts in anoraks. It is highly unlikely this bothered him.

"Cook seldom seeks to draw attention to himself. He will not be tweeting his joy to the nation tonight. In fact he looked relieved to get this out of the way as well as delighted that he had led England to another series victory."