The UK will fail to achieve a target of offering gigabit-capable broadband to 85% of the UK by 2025, MPs have warned.
Initially, the government had aimed for nationwide coverage within five years.
But targets were scaled back when it emerged that only 25% of the promised £5bn funding would be available.
The Commons Digital, Culture, Media and Sport Committee said the cuts, paired with a "lack of effective planning" meant the UK could end up playing catch-up to other countries.
The report said there was "no genuine belief" from within the sector that the government's current goals were possible within its current timeframe.
“The government’s decision to abandon its 2025 gigabit-capable broadband target within weeks of ministers reassuring us of their commitment to it was a belated recognition that it was unrealistic and unachievable, underlining concerns we’d heard from industry," said committee chairman Julian Knight.
On the same day as the committee's scathing report, the government also laid out the next steps in its plan.
It said homes and businesses that did not yet have access to gigabit-capable broadband would be prioritised in the ongoing roll-out.
Lloyd Felton, of County Broadband, said this would be crucial in making sure the UK's broadband was fit for future generations.
“Continued growth in the rollout of full-fibre broadband is much-needed, as a recent Ofcom report revealed only 18% of the UK can access full-fibre services.
"It is vital that we take the opportunities to invest in full-fibre infrastructure now, to ensure Britain’s broadband is accessible to all UK properties," he added.
The committee also echoed concerns from within the telecoms industry that the government would fall short of its 5G coverage target, leaving some areas without connectivity.
The government had previously announced its target for majority 5G coverage in the UK by 2027 as part of its £5bn plan.
However, the DCMS said the plans in their current state failed to address problems with coverage in hard-to-reach rural areas.
About 9% of the UK has little or no access to 4G networks from any provider.
“The government’s target to deliver to the majority of the population, rather than the majority of the country, risks repeating the same errors that led to mobile ‘not-spots’," said Mr Knight.
"If investors cherry-pick areas of high population, it leaves people in remote rural areas without a hope."
Mr Knight added that current plans risked "embedding digital inequality rather than solving it".
Honest Mobile founder Andy Aitken urged the government to put addressing the UK's current coverage issues ahead of its 5G plans.
"Even people in central London - where coverage is best - still find themselves in not-spots and without a connection during rush hour," said Mr Aitken.
He added: "Lockdown has only highlighted the importance of giving high-quality internet access to everyone wherever they live in the UK."
Following a ruling in July, the UK's mobile providers are banned from using Huawei 5G equipment after 31 December.
They must also remove all the Chinese firm's 5G kit from their networks by 2027.
The legislation is expected to result in a delay of at least two years to 5G roll-out, with additional costs of up to £2bn.