'With continued solid customer growth, we are well on track to deliver on our outlook for the year.
I would like to open this quarter's result looking back to the recent devastating floods in Belgium. My thoughts go to all the victims and their families in the affected regions. At the same time, over the past 2 weeks, I have been astonished by the commitment of many Proximus colleagues. These events have unveiled, once again, the important societal role we play, firstly through our infrastructure and the connectivity it provides, but also more broadly as a key part of the Belgian economic fabric of society. The last two weeks have also sent us a vivid reminder of our climate vulnerability and the relevance of our sustainability ambition as part of our #inspire2022 strategy.
Looking back at the second quarter, we saw strong continued commercial traction for our products and services. In a highly competitive setting, we delivered another consecutive quarter of customer growth for our main telecom customer bases. This is especially true for the premium segments of the market, as demonstrated by the nice increase in our TV base by +12,000 subscriptions. We also closed another strong quarter for Mobile, growing the Postpaid base by 48,000 subscriptions. These results demonstrate solid mobile growth on the Enterprise segment as well as the continued success of our Flex range, reaching 619,000 subscriptions. Our Consumer convergence base grew by 18,000 over the quarter, with customers generating a higher-than-average ARPC.
With the green light received from the Belgian Competition Authority, I am delighted to welcome Mobile Vikings to the Proximus family, the leading brand for the Belgian digital lovers and perfectly complementing our Scarlet and Proximus offers.
Our Fiber acceleration is delivering according to plan. During the second quarter, we brought the average weekly deployment up to 7,400 homes and business passed, leading to an additional 89,000 premises passed with Fiber and bringing our coverage to just over 10%. The superiority of Fiber was clearly demonstrated in June with a 25Gbps world-record in Antwerp, and this is also materializing in our customer numbers. Over the second quarter of 2021, we recorded 14,000 Fiber net adds, totaling 90,000 customers on our Consumer Fiber offers at end June 2021.
As announced yesterday, I'm happy that our Fiber partnership for the southern part of Belgium with Eurofiber has been cleared by the European authorities. The newly created joint-venture Unifiber will pass at least 500,000 premises with Fiber by 2028. With our two Fiber partnerships now being operational, and the ramp up of our own Fiber deployment, we are well on track to realize our ambition to pass a total of 4.2 million premises in Belgium by 2028.
As for our Enterprise segment, the ongoing transformation is being well-managed, with its effects offset by continued strong results for Telecom services. Specifically, for ICT, the increased digital adoption is bringing structural opportunities with a particular focus on cloud, security, IoT and collaboration. In that context, our converged Telco-ICT solutions and our emerging end-to-end servicing offers are leading to an increasing share of higher margin ICT Service revenues.
Beyond our domestic operations, TeleSign continued to show strong revenue growth, up by 22.5% on a constant currency basis, driven by both Programmable Communications and Digital Identity services. The second quarter ended with a strong sales pipeline, which will support a continued double-digit revenue trajectory in the second half of the year.
With the Covid-19-effect on worldwide travel annualized, our segment BICS showed a noticeable trend improvement from previous quarters. Especially revenue from BICS' core services showed a strong increase compared to the previous year, driven by the solid growth in Application-to-Person messaging and Cloud Communications, both in the Telecom and Digital enterprise market.
Overall, we are very pleased with our strategic progress and the financial results achieved so far in 2021. For the remainder of the year, there is still some uncertainty on the speed of recovery from Covid-19 restrictions. Despite this uncertainty we are confident to meet our full-year guidance, expecting for 2021 on an organic basis an Underlying Domestic revenue close the level of 2020, an Underlying Group EBITDA between EUR 1750-1775 million and Capex, excluding spectrum and football rights, close to EUR 1.2 billion. The level of Net debt/EBITDA is expected to remain below 1.6X.'