In 2007, I went to a beach and had a premonition of dystopia. Travellers sometimes deem places they consider dull or provincial as “stuck in the past” or “quaintly outdated”, but Carita on the west coast of Java, Indonesia on that chokingly humid July morning was for me a brief and bitter taste of a future that humanity must avoid. Plastic bags, boxes and wrappers – plus the odd rusty, dented oil drum – rode the sluggish waves onto the black sand. While locals were picnicking amid more rubbish on the beach, they were too wise to swim in the water. My most vivid memory of Carita sums up the raw irony and surrealism of human-made waste’s attack on nature: untold empty packets of krupuk, a starch snack flavoured with long-dead fish, congealed into a plasticky mush that was harming still-live fish. 

Fourteen years later almost to the day, I’m standing on the Milton side of Langstone Harbour and relieved it’s not anywhere as bad as Carita was. But it isn’t spotless either. Along the beach’s strandline is a cordon of seaweed that has trapped and absorbed garishly-fonted chocolate bar wrappers, the polythene lid from a Tesco spicy chicken salad, the ripped-off corners of sweet packets and two languidly deflated party balloons. Louis and I ponder these items’ backstories. How did a balloon from a children’s birthday or some such occasion end up here? What a journey. 

Two women on a morning stroll tell us they haven’t seen any plastic waste at all, only glass bottles and tin cans. Louis and I puzzle over this and then realise that the strandline is a good twenty metres up from the section of the beach people walk along. And even if they did follow the seaweed trail, are strollers so used to seeing small-scale refuse that they don’t register it as out of the ordinary? Part of the confusion could be down to some natural objects resembling plastic ones; the artificial-seeming white of a cuttlefish skin could be mistaken for a lid, seashells for caps and stoppers. 

Further along, at the point where the beach elevates into grassy dunes, is a rock pool with a shipwreck vibe; metal poles like masts and rudder-like rings poke through the water’s surface. But these aren’t boat components, they’re building materials, as is a plastics-packed carpet tile stuck to the pool’s bed. This stuff must have been fly-tipped, as most of it’s too heavy to have been borne on the waves. On any scale of shameless littering, fly-tipping must come low, or at least lower than discarding the takeaway bags and boxes that account for70% of plastic pollution on British shores.

Opposite the despoiled rock pool, the low-tide marshes must be healthy enough to support a sprightly procession of swans who pester us as Louis sits and draws. On closer inspection, though, there’s a latex glove positioned so that it looks like someone is trying to reach out from under the mud. Nearby is a half-submerged pink frisbee, as if the glove-owner was playing around before falling foul of the marsh. Then comes the biggest single piece of plastic trash we’ll see on our trip: an abandoned fibreglass runabout. According to the women, it’s “been there for years and years”. 

The proximity of Eastney Marina could explain the presence of this diminutive ghost ship, along with an oblong of beige plastic – that looks to have fallen off another boat – forming an askew bridge over one of the labyrinthine, tidal channels.

Eastney and Southsea beaches look cleaner, but the higher tide could be masking the sorts of blemishes that were on full display at Langstone Harbour. Father-and-son fishermen, their rods arching high into the midday sparkle of the sea, tell us that, of all the beaches they like to hunt off, Southsea’s is by far the dirtiest. 

“The plastic situation’s bad now,” says the fortysomething son. “If you were to pick through the stones here, you’d find plenty of that crap.” Does plastic ever get caught up with his fishing line? “Oh yeah.”

“When the holidaymakers are down, it’s terrible,” says his sixtysomething dad. “It’s all about money. It’s cheaper to have plastic packaging and all that, but there’s not a care in the world about what happens after.”  

What can be done?

“I applaud the litter picking groups you see round here sometimes,” says the son. He points to his dad. “And they didn’t have plastic bags in the forties and fifties when he grew up. Perhaps we can get back to paper bags.”

As we move on, I’m haunted by what the younger fisherman said about hidden waste. Before this trip, I’d read that microplastics – so small as to be invisible to the human eye – can seriously injure wildlife. I wince at seagulls pecking at a bloated tangle of seaweed.

As we near the areas of Southsea Beach where people flock to eat and drink, we spot, again on the strandline, washed-up plastic straws (banned in the UK since October last year). There are also polythene shards of various length and width; some like shoelaces, others like flags. At the foot of the concrete slope before the war memorial are coffee cups, more sweet wrappers and a couple of those tiny translucent tubes that cigarette filters come in. More straws mar Clarence Pier, in addition to cream-coloured bottle caps that can’t at first glance be told apart from the stones.

While a vast Isle of Wight ferry casts its shadow over us, we look over the guardrail of the Point into the water lapping the wall. Again, sadly, the seaweed has attracted the worst of the waste. Standing out from the fast-food beaker (with plastic lid intact) entwined by the seaweed and the now-ubiquitous bottle tops is a bigger item whose origin I can’t figure out. It’s patently plastic, though, and honey-coloured, barrel-shaped and fist-sized.

The dubious climax to our journey is the sluice gate in the harbour, just near the Millennium Trail. From all over the region – and not least Gunwharf Quays mall, the consumption capital of Portsmouth – the sluice has sucked up a veritable bonanza: jagged chunks of polystyrene; a polypropylene takeaway fork; a spray can with plastic nozzle; numerous small boat parts; a condom wrapper; two mineral water bottles.

In Gunwharf itself, I have another premonition of sorts. A section of the wharf that’s exposed to the water is occupied by remote control racing boats. In a far corner of that section floats a plastic bottle that’s absurdly out-of-scale with the boats, which are mini-Wightlink ferries and police launches. Like a 1950s B-movie, I imagine the oversized bottle – that to me symbolises the whole plastic waste scourge – bobbing menacingly over to these vessels – that represent human civilisation, travel, trade, law and so forth – and capsizing them with a couple of well-timed rams.