Image copyright Getty Images Image caption Just 5% of Wales' streets are litter free, claim councils

It seemed like the perfect proposal - tackling litter louts without hitting the council tax payer in the pocket.

A private firm targets those dropping rubbish or letting dogs foul our pavements and hits the offenders with fines of up to £100.

The company supplies the manpower and knowhow, with fines covering their bills and no cost to the local council.

But is type of relationship with private enforcement firms on the rocks in north Wales, especially with Cheshire-based Kingdom Services?

It has been the chosen company to handle litter enforcement by many councils.

But it seems some in north Wales are now considering a break up in the relationship.

This week, councillors in Flintshire signalled their wish to review how they deal with litter bugs in the future - and their relationship with Kingdom amid claims of "overbearing behaviour".

Last week it was Denbighshire council making very similar noises.

The problem may be one of perception and politics as much as facts and figures.

It was highlighted again on Thursday, when an adventure park owner in Conwy county voiced anger over Kingdom enforcement officers handing out fixed penalty fines on its land.

Kingdom was quick to point out it had permission to be there from its employer - the local council - and also had the law on its side as enforcement agents are allowed on to private land if a littering offence is occurring.

But there is clearly some resentment towards those dishing out the fines.

'Vigilante threats'

Tempers were frayed when the issue was discussed by Denbighshire council a week ago.

The firm was due to attend a scrutiny committee to discuss future arrangements, with its contract due to end in November.

Instead it sent a letter - stating it feared for safety of staff from a "vigilante group" that could have been present.

"Over the last year, due to a malicious disinformation campaign, Kingdom employees have been the subject of threats, with their address posted on social media next to captions such as 'we know where you live'," wrote the company.

"Pictures of our employees and even their children have been posted online, prompting Kingdom to call the police. Car windows have been smashed and recently two tyres were vandalised using a drill, to name but a few of the serious incidents.

"In what has become a highly charged environment, Kingdom continues to take a view on a case by case basis as to whether we can continue working under such circumstances.

"We are confident that the report will confirm the quality of service we have always provided, and would be happy to answer any committee questions in writing, or meet in a closed session."

Image copyright Getty Images Image caption Clearing litter from Welsh roads costs £3.5m a year, according to the Keep Tidy Wales group

Indeed, the report's authors did recommend that the council support the partnership with Kingdom.

But councillors saw red over the non-appearance, with one calling it "disgusting" that the company was not present.

Instead of backing the report, the scrutiny group ordered the council to re-examine how it tackles environmental crime, including looking at bringing services in-house or collaborating with other councils.

Colleagues in neighbouring Flintshire council have also adopted the same approach, and have asked its cabinet to review how it enforces action on litter louts.

Pilot partnerships with Kingdom in both Anglesey and Gwynedd ended sooner than anticipated earlier this year, when the company withdrew from the arrangement with both authorities after taking a "commercial decision".

So what about the last two outstanding councils; Conwy and Wrexham?

Wrexham has a two-year deal with Kingdom with an option to extend the contract by a further year to 2019. It must take a decision on that in the autumn, and is setting up a group to consider the matter.

But the authority has been consistent in its support of a "zero tolerance" approach to littering, and has backed how Kingdom has enforced it, stating last December that the enforcement work by Kingdom was "proving to be a success for the council".

It is also make-your-mind up time for Conwy too.

Kingdom has been working for the council across the county since 2013. It will be discussing its future litter enforcement strategy in July.

The company itself said it was relaxed about the approaches being adopted by councils in north Wales.

It stressed it was the firm's own decision to withdraw from the arrangements with Anglesey and Gwynedd.

It also noted contracts with most of the councils always had fixed end dates, when new contracts would then need to be put out for tender.

Kingdom said recent discussions at councils like Flintshire and Denbighshire simply reflected that reality.

And if those councils want to keep private firms on their books to handle enforcement in the future - Kingdom will then be able to decide whether to bid for them or not.