Thread on Prediction of Coming of Britishers in Shāstras :

Bhavishya Puran talks about Gurundas many times .
Who are Gurundas ?

Bhavishya Puran itself clears it .

Suta Goswami said: “At the present time, the Kali-yuga has already passed its 3000 years. Now the king Sankha is ruling the earth and in the mleccha countries the king named Sakapat is ruling. Please hear about how they came up."

When the Kali-yuga passed 2000 years, the dynasty of mlecchas increased. They created many paths to grow and gradually the whole earth become full of mlecchas. The spiritual master and teacher of the mlecchas was named Musa (Moses ) .

He was residing on the bank of the river Sarasvati, and he spread his doctrince throughout the whole world. As soon as Kali-yuga started, the devotion to the Lord and the language of the Vedas were destroyed.

There are four kinds of mleccha languages: Vraja-bhasa, Maharastri, Yavani and Garundika. In this way there are four million kinds of other languages.

For example: paniyam (water) is called pani, bubhuksa-hunger is called bhukh. Paniyam-drinking is called papadi and bhojanam-eating si called kakkanam. Isti is called suddharava, istini is called masapavani, ahuti is called aju and dadati is called dadhati.

The word pitri is called paitara and bhrata is bather and also pati. This is the yavani lanugage in which the asva is called aspa, Janu is jainu and sapta-sindhu is called sapta-hindu. Sindhu became Hindu .

Now you hear about Gurundika language. Ravi-vara (the first day of the week) is called sunday, phalguna and chaitra months are called pharvari (February). Sasti is called sixty, these kinds of examples are there.

Crime is becoming prominent in the holy place of Sapta-puri. Gradually the people of Aryavata are becoming theives, hunters, bhillas and fools. The followers of mleccha-dharma in foreign countries are intelligent and having good qualities, whereas the people of

Aryavarta are bereft of good qualities. Thus the ruling of mlecchas is also in Bharata (India) and its islands. Knowing all this, O great and intelligent sage, you should just perform the devotional service to Lord Hari.

Now it's clear who are Gurundas . Gurundas are Britishers and Gurundas is English . Aanglabhasha is another name for English however here it is used as Gurundika

Gurundas are Britishers . Gurundas are people speaking Gurundika language which is English .

Now let's se this prophecy in Srimad Bhagwatamto have a clear picture .
Srimad Bhagwatam is popular for its authenticity as there are total 100+ commentaries on this Purana from 14th

century to 21st century . Earliest complete commentary which is available completely today is by Shridhar Swami who was born in 14th century .

So there is no question of Interpolation mad after coming of Muslims or britishers in Srimad Bhagwatam

The First Chapter of 12th canto of Srimad Bhagwatam briefly describes the future kings of the dynasty of Magadha and how they become degraded because of the influence of the Age of Kali.There were twenty kings who ruled in the family of Pūru, in the dynasty of the sun-god,

Counting from Uparicara Vasu to Purañjaya. After Purañjaya, the lineage of this dynasty will become corrupted. Following Purañjaya there will be five kings known as the Pradyotanas, who are then followed by the Śiśunāgas, the Mauryas, the Śuṅgas, the Kāṇvas, thirty

kings of the Andhra nation, seven Ābhīras, ten Gardabhīs, sixteen Kaṅkas, eight Yavanas, fourteen Turuṣkas, ten Guruṇḍas, eleven Maulas, five Kilakilā monarchs and thirteen Bāhlikas

Now Srimad Bhagwatam is the Purana which mentions about Prophecy of Britishers atleast 500–600 years before their real advent . Alberuni mentions Srimad Bhagwatam in his works so this Purana is atleast 1000 years old . The Commentary of Shridhar Swami of 14th

century has this verse . You can check over http://archive.org  for verification . The scanned manuscript is available.

This is the verse mentioning Britishers in Bhagwatam ( Bhagwata Puran )

Śrimad Bhagwatam 12.1.28

ततोऽष्टौ यवना भाव्याश्चतुर्दश तुरुष्कका: ।
भूयो दश गुरुण्डाश्च मौला एकादशैव तु ॥ २८ ॥

Eight Yavanas will then take power, followed by fourteen Turuṣkas, ten Guruṇḍas and eleven kings of the Maula dynasty.

So clearly the Sages could see future and the prediction was fulfilled

In some Puranas instead of the word Maula , Mauna ( Silent ) is there . Gitapress suggests that it means so called silent kings (rulers of democracy